Prepreg, method for producing same, and slit tape prepreg

ABSTRACT

A prepreg is provided that has excellent processability and handleability and that can be processed into a cured product with high heat resistance. Also provided is a method to produce such a prepreg in an industrially advantageous way without being restricted by the types and contents of the matrix resin components used. The prepreg includes at least components [A] to [D] as given below and a preliminary reaction product that is a reaction product of the component [B] and the component [C], at least one surface resin in the prepreg having a storage elastic modulus G′ in the range of 1.0×10 3  to 2.0×10 8  Pa as measured at a temperature of 40° C. and an angular frequency in the range of 0.06 to 314 rad/s: [A] carbon fiber, [B] epoxy resin comprising a m- or p-aminophenol epoxy resin [b1] and either a glycidyl ether epoxy resin or a glycidyl amine epoxy resin [b2] that has two or more glycidyl groups in a molecule, [C] curing agent, and [D] thermoplastic resin.

CROSS REFERENCE TO RELATED APPLICATIONS

This is the continuation application of U.S. application Ser. No.16/475,518, filed Jul. 2, 2019, which is the U.S. National Phaseapplication of PCT/JP2018/001443, filed Jan. 18, 2018, which claimspriority to Japanese Patent Application No. 2017-007304, filed Jan. 19,2017, Japanese Patent Application No. 2017-007305, filed Jan. 19, 2017and Japanese Patent Application No. 2017-201581, filed Oct. 18, 2017,the disclosures of each of these applications being incorporated hereinby reference in their entireties for all purposes.

FIELD OF THE INVENTION

The present invention relates to a prepreg that has excellentprocessability and handleability and provides a cured product with highheat resistance, and a method for the production thereof.

BACKGROUND OF THE INVENTION

Fiber reinforced composite materials consisting of reinforcing fibersuch as glass fiber, carbon fiber, and aramid fiber combined with amatrix resin are lighter in weight compared with competing metallicmaterials or the like, and at the same time excellent in mechanicalproperty such as strength and elastic modulus, and accordingly, they arecurrently used in many fields such as aircraft members, spacecraftmembers, automobile members, ship members, civil engineering andconstruction materials, and sporting goods. In particular, carbon fibersexcellent in specific strength and specific elastic modulus are widelyused as reinforcing fibers in application fields where high mechanicalproperty is required. In addition, thermosetting resins such asunsaturated polyester resin, vinyl ester resin, epoxy resin, phenolresin, cyanate ester resin, and bismaleimide resin are often used asmatrix resins, and in particular, epoxy resins are in wide use becauseof their high adhesiveness to carbon fibers. In applications requiringhigh performance, fiber reinforced composite materials containingcontinuous fibers are used, and in particular, they are generallymanufactured by methods that use prepregs, which are sheet-likeintermediate substrates consisting mainly of reinforcing fibersimpregnated with uncured thermosetting resin compositions. In suchmethods, prepreg sheets are stacked and cured by heating to provide amolded product of a fiber reinforced composite material. Fiberreinforced composite materials manufactured in this way have been usedfor various general industrial applications such as tennis rackets, golfshafts, and fishing poles, but they are now attracting attention asstructural materials for aircraft, which are required to be light inweight, because they have high specific strength and specific stiffness.

Available methods for laminating prepreg sheets include the hand layupmethod, ATL (automated tape layup) method, and AFP (automated fiberplacement) method, but when producing a large composite material such asfor aircraft, automated lay-up methods such as the ATL method and theAFP method, which are higher in productivity than the hand layup method,are used (see, for example, Patent document 1). Among others, the AFPmethod, which is designed to laminate slit tape prepregs (hereinafter,simply referred to as slit tapes) prepared by cutting a prepreg in thefiber direction to produce tape-like sheets, are suitable for producingparts containing a relatively large number of curved surfaces such asaircraft fuselage, and also can be produced with a high material yield,and accordingly, this method has been frequently adopted in recentyears.

In the AFP method, about ten to several tens of narrow slit tapes withwidths of 3 to 13 mm are passed through guide rolls, collected on amachine head, and laid up on a substrate in order to improve thelamination efficiency. In this step, as the guide roll and the slit taperub each other, the epoxy resin composition contained in the slit tapecomes out and adheres to the guide roll, leading to the problem of asubsequent decrease in the processability of the slit tape. In the aboveprocess, the unwinding of the slit tapes and their collection on themachine head are performed under low temperature conditions, for example20° C., where the storage elastic modulus (hereinafter referred to asG′) of the epoxy resin composition becomes higher in order to preventthe adhesion of the epoxy resin composition to the guide rolls. In orderto secure sufficient adhesion between the substrate and slit tapes andbetween slit tapes and other slit tapes during the lamination step, theslit tapes are often heated by an infrared heater or the like to raisethe temperature as they are adhered.

In Patent document 2, unidirectional prepregs in which reinforcing fiberbundles are not twisted are cured to a degree where the resin conversionof the matrix resin composition reaches 20% to 70% to provide semi-curedprepregs, and subsequently they are cut in the fiber direction of thereinforcing fibers to produce slit tapes. It is described that they arehigh in reinforcing fiber straightness and resistant to twisting andthey are also low in tape face tackiness (hereinafter referred to astack) and high in handleability.

Patent document 3 discloses a slit tape in which an epoxy resincomposition having a viscosity of 1.0×10⁵ to 1.0×10⁹ Pas at 25° C. and aglass transition temperature of 7° C. to 15° C. is located near both ofthe thickness-directional surfaces of the prepreg while an epoxy resincomposition having a viscosity of 5.0×10² to 1.0×10⁵ Pas at 25° C. islocated in the thickness-directional central portion and it is describedthat the aforementioned adhesion of the epoxy resin composition to guiderolls is reduced and that the composition has excellent drapability.

-   -   Patent document 1: Published Japanese Translation of PCT        International Publication JP 2008-517810    -   Patent document 2: Japanese Unexamined Patent Publication        (Kokai) No. 2016-155915    -   Patent document 3: Japanese Unexamined Patent Publication        (Kokai) No. 2010-229211

SUMMARY OF THE INVENTION

The slit tape obtained by the production method described in Patentdocument 2 is already in such a highly cured state that it cannotundergo significant twisting and accordingly, it lacks in drapabilityand fails to have sufficient steering ability for the curved surfaces ofthe guide rolls. Therefore, it is difficult to apply the tape to the AFPmethod.

The slit tape described in Patent document 3 is still so high intackiness that prepreg sheets adhere easily to each other at roomtemperature, indicating that the tackiness is not sufficiently low andthe molecular weight is relatively high. Since epoxy resin that is solidat room temperature is used for viscosity adjustment, it is difficult toreduce the tackiness largely while allowing a cured product with highheat resistance to be obtained.

In view of the above situation, an object of the present invention is toprovide a prepreg having high drapability, serving to produce a slittape prepreg that suffers a lower degree of adhesion of the epoxy resincomposition contained in the slit tape prepreg to the guide rolls whenprocessed by the AFP method to ensure an increased productivity ofcarbon fiber reinforced composite material and also serving to provide acured product (carbon fiber reinforced material) having high heatresistance, and also provide a method for the production thereof.

The present inventors conducted intensive research to solve the aboveproblem, and arrived at the invention described below. Specifically, thepresent invention provides a prepreg including at least the components[A] to [D] given below and a preliminary reaction product that is areaction product of the component [B] and the component [C], at leastone surface resin in the prepreg having a storage elastic modulus G′ inthe range of 1.0×10³ to 2.0×10⁸ Pa as measured at a temperature of 40°C. and an angular frequency in the range of 0.06 to 314 rad/s.

-   -   [A] carbon fiber,    -   [B] epoxy resin,    -   [C] curing agent, and    -   [D] thermoplastic resin.        Furthermore, the slit tape prepreg according to the present        invention is produced by slitting the aforementioned prepreg.

In addition, the present invention provides a prepreg production methodincluding a step for performing heat-treatment or energy irradiation ofa prepreg precursor containing at least the components [A] to [D] givenbelow to provide a prepreg containing at least one surface resin havinga storage elastic modulus G′ in the range of 1.0×10³ to 2.0×10⁸ Pa asmeasured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s.

-   -   [A] carbon fiber,    -   [B] epoxy resin,    -   [C] curing agent, and    -   [D] thermoplastic resin.        Furthermore, the present invention provides another prepreg        production method including a step for performing heat-treatment        or energy irradiation of an epoxy resin composition containing        at least the components [B] and [C] given above and a subsequent        step for impregnating the component [A] given below therewith,        to provide a prepreg containing at least one surface resin        having a storage elastic modulus G′ in the range of 1.0×10³ to        2.0×10⁸ Pa as measured at a temperature of 40° C. and an angular        frequency in the range of 0.06 to 314 rad/s.

The present invention can provide a prepreg having high drapability,serving to produce a slit tape prepreg that suffers a lower degree ofadhesion of the epoxy resin composition contained in the slit tapeprepreg to the guide rolls when processed by the AFP method to ensure anincreased productivity of carbon fiber reinforced material and alsoserving to provide a cured product (carbon fiber reinforced material)having high heat resistance, and also provide a method for theproduction thereof.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS OF THE INVENTION

The present invention will be described more in detail below.

The prepreg according to the present invention is a prepreg including atleast the components [A] to [D] given below and a preliminary reactionproduct that is a reaction product of the component [B] and thecomponent [C], at least one surface resin in the prepreg having astorage elastic modulus G′ in the range of 1.0×10³ to 2.0×10⁸ Pa asmeasured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s.

-   -   [A] carbon fiber,    -   [B] epoxy resin,    -   [C] curing agent, and    -   [D] thermoplastic resin.        As a result of adopting this constitution, at least one surface        resin in the prepreg has a moderately high G′ of 1.0×10³ to        2.0×10⁸ Pa in the wide measuring angular frequency of 0.06 to        314 rad/s, thus allowing the production of a slit tape prepreg        that suffers a lower degree of adhesion of the epoxy resin        composition contained in the slit tape prepreg to the guide        rolls when processed by the AFP method to ensure an increased        productivity of carbon fiber reinforced material. Furthermore,        the G′ value of the surface resin is not too high and therefore,        a high drapability is maintained. Then, these characteristics        are adjusted properly by combining a preliminary reaction        product, i.e. the reaction product of the component [B] and the        component [C], and a thermoplastic resin, i.e. the component        [D], to allow the prepreg to serve also to produce a cured        product (carbon fiber reinforced material) having heat        resistance.

The prepreg according to the present invention includes the components[A] to [D] and further includes a preliminary reaction product, which isthe reaction product of the component [B] and the component [C] asdescribed above, and takes the form of any one of the first to thirdpreferred embodiments.

According to the first preferred embodiment, the component [B] includesa m- or p-aminophenol epoxy resin [b1] and either a glycidyl ether epoxyresin or a glycidyl amine epoxy resin [b2] that has two or more glycidylgroups in a molecule, and the component [b1] in the prepreg includingthe preliminary reaction product accounts for 10 to 60 parts by masswhile the component [b2] in the prepreg including the preliminaryreaction product accounts for 40 to 90 parts by mass relative to thetotal quantity, which accounts for 100 parts by mass, of the component[B] in the prepreg including the preliminary reaction product. Theadoption of such a constitution serves to provide a prepreg that gives acarbon fiber reinforced material having heat resistance and mechanicalproperty in a good balance.

According to the second preferred embodiment, the prepreg gives a curedproduct having a phase-separated structure in which there is phaseseparation between a phase containing the reaction product of thecomponent [B] and the component [C] as main component and a phasecontaining the component [D] as main component. The adoption of such aconstitution serves to provide a prepreg that gives a carbon fiberreinforced material having a higher impact resistance compared with thecase where the cured matrix resin forms a homogeneous structure.

According to the third preferred embodiment, the component [B] includesan epoxy resin [b5] that contains one or more ring structures havingfour- or more-membered ring and at the same time containing at least oneamine type glycidyl group or ether type glycidyl group directlyconnected to a ring structure, and an epoxy resin [b6] which is tri- ormore-functional, and the component [B] in the prepreg including thepreliminary reaction product accounts for 5 to 60 parts by mass whilethe component [C] in the prepreg including the preliminary reactionproduct accounts for 40 to 80 parts by mass relative to the totalquantity, which accounts for 100 parts by mass, of the component [B] inthe prepreg including the preliminary reaction product. The adoption ofsuch a constitution serves to provide a prepreg that gives a carbonfiber reinforced material having good mechanical property (tensilestrength) at low temperatures.

Each of the components is described in detail below.

The carbon fiber used as the component [A] for the present invention ishigh in specific strength and specific elastic modulus and also high inconductivity, and therefore, used suitably in applications where goodmechanical property and high conductivity are required.

Specific preferred examples of carbon fiber used as the component [A]include acrylic, pitch based, and rayon based carbon fibers, of whichacrylic carbon fiber is particularly preferred because it is high intensile strength.

Acrylic carbon fiber can be produced through, for example, a process asdescribed below.

First, a spinning solution that contains polyacrylonitrile produced frommonomers formed of acrylonitrile as main component is spun by wetspinning, dry-wet spinning, dry spinning, or melt spinning to provide acoagulated thread. Then, the coagulated thread is processed in ayarn-making step to provide a precursor. Then, the precursor issubjected to steps for flameproofing treatment, carbonization, etc., forconversion into carbon fiber, thus providing acrylic carbon fiber. Here,the main component as referred to herein is the monomer component thatis the highest in mass content.

The carbon fiber of the component [A] may be in the form of twistedyarns, untwisted yarns, or twistless yarns. In a twisted yarn, filamentsconstituting the carbon fiber bundles are not oriented in parallel, andfiber reinforced composite material produced therefrom can suffer fromdeterioration in mechanical property, and therefore, untwisted yarns andnon-twisted yarns are preferred because they give fiber reinforcedcomposite materials having moldability and strength characteristics in agood balance.

The carbon fiber of the component [A] preferably has a tensile modulusof 200 to 440 GPa. The tensile modulus of carbon fiber depends on thedegree of crystallinity of the graphite structure formed in the carbonfiber, and the elastic modulus increases with an increasing degree ofcrystallinity. Furthermore, the conductivity also increases with anincreasing degree of crystallinity. If the carbon fiber of the component[A] has a tensile modulus in this range, it is preferable because itgives a fiber reinforced composite material having conductivity,stiffness, and strength all in a good balance at a high level. It ismore preferable for the carbon fiber to have a tensile modulus of 230 to400 GPa, and it is still more preferable for the carbon fiber to have atensile modulus of 260 to 370 GPa. Here, the tensile modulus of carbonfiber is measured according to JIS R7601-2006.

Commercial products of carbon fiber that can be used as the component[A] include Torayca® T800G-24K, Torayca® T800S-24K, Torayca® T810G-24K,Torayca® T700G-24K, Torayca® T300-3K, and Torayca® T700S-12K (allmanufactured by Toray Industries, Inc.).

The epoxy resin [B] to use for the present invention is a compoundhaving one or more epoxy groups in one molecule.

Specific examples of the epoxy resin [B] to use for the presentinvention include aromatic glycidyl ethers produced from a phenol havinga plurality of hydroxyl groups, aliphatic glycidyl ethers produced froman alcohol having a plurality of hydroxyl groups, glycidyl aminesproduced from an amine, glycidyl esters produced from a carboxylic acidhaving a plurality of carboxyl groups, and epoxy resins having anoxirane ring.

For the first preferred embodiment of the present invention, a m- orp-aminophenol epoxy resin [b1] and either a glycidyl ether epoxy resinor a glycidyl amine epoxy resin [b2] that has two or more glycidylgroups in a molecule are used as the epoxy resin [B]. This serves toprovide a prepreg that has high processability and handleability andgives a cured product with high heat resistance and mechanical property.

From the viewpoint of containing a cured resin simultaneously high intoughness, elongation percentage, and heat resistance, it is preferablefor the component [b1] to account for 10 to 60 parts by mass, morepreferably 15 to 55 parts by mass, and still more preferably 20 to 50parts by mass, relative to the total quantity, which accounts for 100parts by mass, of the component [B].

The component [b1] is preferably at least one selected from the groupconsisting of epoxy resins having structures as represented by theformula (2) given below, and derivatives thereof.

wherein R³ and R⁴ in formula (2) represent at least one selected fromthe group consisting of a hydrogen atom, aliphatic hydrocarbon groupcontaining 1 to 4 carbon atoms, alicyclic hydrocarbon group containing 4or less carbon atoms, and halogen atom.

If the structures of R³ and R⁴ in formula (2) are too large, the epoxyresin composition can be too high in viscosity to cause a decrease inhandling ability, and the compatibility between the m- or p-aminophenolepoxy resin and other components of the epoxy resin composition candecrease, resulting in deterioration in the effect of giving a carbonfiber reinforced material with improved mechanical property.

Specific examples of the component [b1] include, for example,triglycidyl-p-aminophenol, triglycidyl-m-aminophenol, and derivativesand isomers thereof.

In particular, R³ and R⁴ are each preferably a hydrogen atom from theviewpoint of compatibility with other epoxy resins, and more preferablytriglycidyl-p-aminophenol or triglycidyl-m-aminophenol from theviewpoint of heat resistance. From the viewpoint of fire retardance, R³and/or R⁴ may be substituted by halogen atoms such as CI and Br as apreferred embodiment.

Commercially available products of m- or p-aminophenol epoxy resin [b1]are listed below.

Commercial products of aminophenol epoxy resin include Sumiepoxy® ELM120and ELM100 (both manufactured by Sumitomo Chemical Co., Ltd.), jER® 630(manufactured by Mitsubishi Chemical Corporation), and Araldite® MY0500,MY0510 and MY0600 (all manufactured by Huntsman Advanced MaterialsGmbh).

The component [b2], which is used in combination with the component[b1], is either a glycidyl ether epoxy resin or a glycidyl amine epoxyresin that has two or more glycidyl groups in a molecule, and it is animportant component from the viewpoint of heat resistance represented byglass transition temperature of cured products and the viscosity of thepreliminary reaction product described later. It should be noted thataminophenol epoxy resin is not a glycidyl ether epoxy resin or aglycidyl amine epoxy resin. If an epoxy resin having less than twoglycidyl groups in a molecule is used, a cured product produced byheating and curing its mixture with a curing agent as described laterwill be low in glass transition temperature in some cases. Preferredexamples of such an epoxy resin include, for example, bisphenol epoxyresins such as bisphenol A epoxy resin, bisphenol F epoxy resin,bisphenol AD epoxy resin, and bisphenol S epoxy resin; brominated epoxyresins such as tetrabromobisphenol A diglycidyl ether; and others suchas alicyclic epoxy resin, diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiphenyl ether, xylene diamine, constitutional isomersthereof, and substances produced by converting a derivative having ahalogen atom or an alkyl substituent containing three or less carbonatoms, used as precursor, into a glycidyl compound. More specifically,they include glycidyl amine epoxy resins such as tetraglycidyldiaminodiphenylmethane, glycidyl compounds of xylene diamine,tetraglycidyl diaminodiphenyl sulfone, and tetraglycidyl diaminodiphenylether.

These epoxy resins may be used singly or as an appropriate mixture inorder to give a carbon fiber reinforced material, which is produced bycuring a prepreg according to the present invention, having intendedmechanical property and heat resistance.

In order to obtain a carbon fiber reinforced material having improvedtoughness, it is preferable to contain a bisphenol epoxy resin as thecomponent [b2], whereas in order to obtain a carbon fiber reinforcedmaterial having improved heat resistance and elastic modulus, it ispreferable to contain a glycidyl amine epoxy resin as the component[b2].

Furthermore, the inclusion of a plurality of epoxy resins havingdifferent flow characteristics is effective for fluidity control of thematrix resin when heat-curing the prepreg obtained. For example, if thematrix resin is high in fluidity before its gelation in the heat curingstep, disturbance in the orientation of carbon fibers can occur, or thematrix resin can flow out of the system to alter the fiber volumecontent out of the predetermined range, possibly resulting in a carbonfiber reinforced material having deteriorated mechanical property.

In the case where the component [b1] and the component [b2] are used incombination, if the content of the component [b2] is small, itcontributes little to the mechanical property of the carbon fiberreinforced material whereas if the content is too large, the heatresistance can decrease in some cases when the component [b2] is abisphenol epoxy resin or the toughness can decrease in some cases whenthe component [b2] is a glycidyl amine epoxy resin. Therefore, from theviewpoint of control of the heat resistance and resin viscosity and alsofrom the viewpoint of the elongation percentage and toughness of theresin, it is preferable for the component [b2] to account for 40 to 90parts by mass, more preferably 45 to 85 parts by mass, and still morepreferably 50 to 80 parts by mass, relative to the total quantity, whichaccounts for 100 parts by mass, of the component [B].

According to the second preferred embodiment of the present invention,the prepreg gives a cured matrix resin having a phase-separatedstructure in which there is phase separation between a phase containingthe component [B], the component [C], and the reaction product of thecomponent [B] and the component [C] as main components and a phasecontaining the thermoplastic resin of the component [D] as maincomponent. This serves to provide a carbon fiber reinforced materialhaving a higher impact resistance compared with the case where the curedmatrix resin forms a homogeneous structure. The main component asreferred to herein is the component of each phase that is the highest inmass percentage.

The phase-separated structure in which there is phase separation betweena phase containing the component [B], the component [C], and thereaction product of the component [B] and the component [C] as maincomponent and a phase containing the component [D] as main component asreferred to herein is a structure in which there are two separatedphases, namely, a phase containing the reaction product of the component[B] and the component [C] as main component and a phase containing thecomponent [D] as main component, with the structural period being in therange described later. Unless there occurs a decrease in the interfacestrength between the two separated phases, the phase-separated structurehas a larger impact resistance improving effect with an increasing masspercentage of the main component, and therefore, the mass percentage ofthe main component is preferably 80 mass % or more, more preferably 90mass % or more, and still more preferably 95 mass % or more.

Such a phase-separated structure is preferably a sea-island structure ora bicontinuous structure from the viewpoint of isotropy of materialcharacteristics, and particularly preferably a sea-island structure fromthe viewpoint of solvent resistance. Here, a sea-island structure is adispersed structure in which a plurality of particle-like domains thatcontain the island component as main component are dispersed in a matrixthat contains the sea component as main component.

Here, the term “particle-like” means a spherical, ellipsoidal, or redblood cell-like shape, a shape of granulated material formed ofcoagulated spherical or ellipsoidal particles, or a shape of amorphousgranular matter or granulated material thereof.

Here, the matters to be noted include the average particle diameter ofthe domains in the sea-island structure, and the structural period anduniformity of the bicontinuous structure. If the size is below a certainlimit, the structure can exhibit physical properties better than thephysical properties of each resin component, and the resin componentscan make up for each other's disadvantages. If the size is above acertain limit, each resin component can exhibit its own goodcharacteristics. After curing the epoxy resin composition according tothe present invention, therefore, the phase-separated structurepreferably has a structural period of 0.01 μm to 50 μm, more preferably0.03 to 10 μm, and still more preferably 0.05 to 5 μm.

Here, the structural period of phase separation is defined as follows.In the case of a sea-island structure, it is the average particlediameter of the domains.

The existence of a sea-island structure can be examined by, for example,curing the prepreg to prepare a carbon fiber reinforced material,embedding it in an epoxy resin designed for electron microscopy, furthercuring it, cryo-cutting it to a thickness of 0.1 μm, and observing across section by a transmission electron microscope (for example,H-7100, manufactured by Hitachi, Ltd.).

Here, when observing the phase structure by electron microscopy,pre-treatment may be performed using various generally known stains topermit clear observation of the phase structure.

From the viewpoint of developing a toughness and impact resistanceimproving effect as a result of the formation of a sea-island structure,the average particle diameter of the domains is preferably 50 μm orless, more preferably 10 μm or less, still more preferably 5 μm or less,and particularly preferably 1 μm or less. Here, the lower limit ispreferably 0.05 μm. If the average particle diameter of the domains isoutside the above range, the toughness and impact resistance improvingeffect will be small or cannot be realized in some cases.

For the second preferred embodiment of the present invention, variousgenerally known compatibilizers can be used to control the averageparticle diameter of the domains.

Here, a compatibilizer is a block copolymer, graft copolymer, randomcopolymer, etc., that works to decrease the free energy at the interfacebetween phase-separated regions to permit easy control of the averageparticle diameter of the domains and the distance among the domains in asea-island structure.

Here, the average particle diameter of the domains can be determined bythe method described below.

<Average Particle Diameter of Domains>

As described above, the prepreg is cured to prepare a carbon fiberreinforced material, and it is embedded in an epoxy resin designed forelectron microscopy and further cured, followed by cryo-cutting it to athickness of 0.1 μm and observing a cross section by a transmissionelectron microscope (for example, H-7100, manufactured by Hitachi,Ltd.). From the transmission electron microscopic photographs obtained,50 domains are selected at random and their cross sections are measuredand converted to diameters of perfect circles that have the same area asthem, which are averaged to give the average particle diameter of thedomains.

In the case of a bicontinuous structure, three straight lines withpredetermined lengths are drawn randomly on a microscopic photograph,and the intersections between the straight lines and the phase-to-phaseinterfaces are determined. Then, the distance between each pair ofadjacent intersections is measured and the number average of thedistance measurements is adopted as structural period. Such a line witha predetermined length is defined as follows on the basis of microscopicphotographs. For a specimen with an assumed structural period of theorder of 0.01 μm (0.01 μm or more and less than 0.1 μm), a photograph istaken at a magnification of 20,000 times and the predetermined length isthe length of a 20 mm line (1 μm length on the specimen) drawn on thephotograph, and similarly, for a specimen with an assumedphase-separation structural period of the order of 0.1 μm (0.1 μm ormore and less than 1 μm), a photograph is taken at a magnification of2,000 times and it is the length of a 20 mm line (10 μm length on thespecimen) drawn on the photograph. For a specimen with an assumedphase-separation structural period of the order of 1 μm (1 μm or moreand less than 10 μm), a photograph is taken at a magnification of 200times and it is the length of a 20 mm line (100 μm length on thespecimen) appropriately drawn on the photograph, and for a specimen withan assumed phase-separation structural period of the order of 10 μm (10μm or more and less than 100 μm), a photograph is taken at amagnification of 20 times and it is the length of a 20 mm line (1,000 μmlength on the specimen) appropriately drawn on the photograph. If themeasured phase-separation structural period is outside the expected sizerange, relevant areas are observed again at a magnification that suitsthe corresponding order.

For the second preferred embodiment of the present invention, it ispreferable to form a sea-island structure in which particle-like phasescontaining the component [D] as main component are dispersed in thephase containing the reaction product of the component [B] and thecomponent [C] as main component from the viewpoint of mechanicalproperty and solvent resistance of the carbon fiber reinforced material.

To allow a phase-separated structure consisting of a phase containingthe reaction product of the component [B] and the component [C] as maincomponent and a phase containing the component [D] as main component tobe formed in the matrix resin after curing a prepreg, the combined useof an aminophenol epoxy resin [b3] such as triglycidyl aminophenol andeither a bisphenol A epoxy resin or a bisphenol F epoxy resin [b4] ispreferred from the viewpoint of prepreg production process features suchas heat resistance, mechanical property, and carbon fiber impregnatingproperty. From the viewpoint of containing a cured resin simultaneouslyhigh in toughness, elongation percentage, and heat resistance, it ispreferable for the component [b3] to account for 30 to 70 parts by mass,more preferably 35 to 65 parts by mass, and still more preferably 40 to60 parts by mass, relative to the total quantity, which accounts for 100parts by mass, of the component [B].

If the content of the component [b4] is small, it contributes little tothe mechanical property of the carbon fiber reinforced material whereasif the content is too large, the heat resistance can decrease largely insome cases. Therefore, from the viewpoint of control of the heatresistance and resin viscosity and also from the viewpoint of theelongation percentage and toughness of the resin, it is preferable forthe component [b4] to account for 30 to 70 parts by mass, morepreferably 35 to 65 parts by mass, and still more preferably 40 to 60parts by mass, relative to the total quantity, which accounts for 100parts by mass, of the component [B].

Among others, liquid bisphenol A epoxy resin and bisphenol F epoxyresin, which are low in viscosity, are particularly preferable from theviewpoint of easy impregnation of carbon fibers with the epoxy resincompositions in a prepreg production process. Compared to liquidbisphenol A epoxy resins, solid bisphenol A epoxy resins will form astructure with a low cross-linking density, which will be low in heatresistance but high in toughness, and accordingly they are used incombination with a glycidyl amine epoxy resin, liquid bisphenol A epoxyresin, or bisphenol F epoxy resin.

Commercially available products of triglycidyl aminophenol useful forthe component [b3] and alkyl-substituted derivatives thereof include thesame ones as those for the component [b1].

Commercial products of bisphenol A epoxy resin useful for the component[b4] include Epon® 825 (manufactured by Mitsubishi ChemicalCorporation), EPICLON® 850 (manufactured by DIC), Epotohto® YD-128(manufactured by Nippon Steel Chemical Co., Ltd.), and DER-331 andDER-332 (both manufactured by The Dow Chemical Company).

Commercial products of the bisphenol F epoxy resin include jER® 806,jER® 807, and jER® 1750 (all manufactured by Mitsubishi ChemicalCorporation), EPICLON® 830 (manufactured by DIC), and Epotohto® YD-170(manufactured by Nippon Steel Chemical Co., Ltd.).

According to the third preferred embodiment, the epoxy resin [B]includes an epoxy resin [b5] that contains one or more ring structureshaving four- or more-membered ring and at the same time containing atleast one amine type glycidyl group or ether type glycidyl groupdirectly connected to a ring structure, and an epoxy resin [b6] which istri- or more-functional. This serves to provide a prepreg that has highprocessability and handleability and gives a cured product with highheat resistance and mechanical strength at low temperatures.

Here, an epoxy resin compound “containing one or more ring structureshaving four- or more-membered ring” either contains one or more singlering structures each having four or more members, such as cyclohexane,benzene, and pyridine, or contains at least one condensed ring structurehaving 4- or more membered rings, such as phthalimide, naphthalene, andcarbazole.

The above expression “amine type glycidyl group or ether type glycidylgroup directly connected to the ring structure of [b5]” means that the Natom is connected to the structure in the case where a ring structuresuch as benzene and phthalimide has an amine type glycidyl group or thatthe 0 atom is connected to the structure in the case of an ether typeglycidyl group. The epoxy resin is either monofunctional ordi-functional in the case of amine type, and the epoxy resin ismonofunctional in the case of ether type. It is referable for thecomponent [b5] to be a di-functional epoxy resin that has a structure asshown by formula (1).

(In the formula, R¹ and R² are at least independently one selected fromthe group consisting of an aliphatic hydrocarbon group having 1 to 4carbon atoms, an alicyclic hydrocarbon group having 3 to 6 carbon atoms,an aromatic hydrocarbon group having 6 to 10 carbon atoms, a halogenatom, an acyl group, a trifluoromethyl group, and a nitro group. Here, nand m are an integer of 0 to 4 and an integer of 0 to 5, respectively.When n or m is an integer of 2 or more, the plurality of R¹'s or R²'smay be either identical to or different from each other. X representsone selected from the group consisting of —O—, —S—, —CO—, —C(═O)O—, and—SO₂—.)

If the content of [b5] is small, it can contribute little to effect ofimproving the mechanical strength of the carbon fiber reinforcedmaterial in some cases whereas if the content is too large, the heatresistance can decrease largely in some cases. Therefore, the content of[b5] in the prepreg including the preliminary reaction product ispreferably 5 to 60 parts by mass relative to the total amount, whichrepresents 100 parts by mass, of the component [B] in the prepregincluding the preliminary reaction product. Furthermore, regarding theepoxy resin of the component [B], a monofunctional epoxy resin is moreeffective in enhancing the strength, and a di-functional epoxy resinrealizes a higher heat resistance. Accordingly, in the case of amonofunctional epoxy resin, the content of [b5] is more preferably 10 to40 parts by mass, and still more preferably 15 to 30 parts by mass,relative to the total amount, which represents 100 parts by mass, of thecomponent [B] in the prepreg including the preliminary reaction product.In the case of a di-functional epoxy resin, it is more preferably 20 to55 parts by mass, and still more preferably 30 to 50 parts by mass,relative to the total amount, which represents 100 parts by mass, of thecomponent [B] in the prepreg including the preliminary reaction product.

Of the epoxy resins useful as [b5] for the present invention,monofunctional ones include, for example, glycidylphthalimide,glycidyl-1,8-naphthalimide, glycidylcarbazole,glycidyl-3,6-dibromocarbazole, glycidylindole, glycidyl-4-acetoxyindole,glycidyl-3-methylindole, glycidyl-3-acetylindole,glycidyl-5-methoxy-2-methylindole, o-phenylphenyl glycidyl ether,p-phenylphenyl glycidyl ether, p-(3-methylphenyl)phenyl glycidyl ether,2,6-dibenzylphenyl glycidyl ether, 2-benzylphenyl glycidyl ether,2,6-diphenylphenyl glycidyl ether, 4-α-cumylphenyl glycidyl ether,o-phenoxyphenyl glycidyl ether, and p-phenoxyphenyl glycidyl ether.

Of the epoxy resins useful as [b5] for the present invention,di-functional ones include, for example, N,N-diglycidyl-4-phenoxyaniline, N,N-diglycidyl-4-(4-methylphenoxy) aniline,N,N-diglycidyl-4-(4-tert-butylphenoxy) aniline, andN,N-diglycidyl-4-(4-phenoxyphenoxy) aniline. In many cases, these resinscan be produced by adding epichlorohydrin to a phenoxy anilinederivative and cyclized with an alkali compound. Since the viscosityincreases with an increasing molecular weight, N,N-diglycidyl-4-phenoxyaniline, which is represented by formula (1) in which both R¹ and R² arehydrogen atoms, is particularly preferred from the viewpoint ofhandleability.

Specifically, usable phenoxy aniline derivatives include 4-phenoxyaniline, 4-(4-methylphenoxy) aniline, 4-(3-methylphenoxy) aniline,4-(2-methylphenoxy) aniline, 4-(4-ethylphenoxy) aniline,4-(3-ethylphenoxy) aniline, 4-(2-ethylphenoxy) aniline,4-(4-propylphenoxy) aniline, 4-(4-tert-butylphenoxy) aniline,4-(4-cyclohexylphenoxy) aniline, 4-(3-cyclohexylphenoxy) aniline,4-(2-cyclohexylphenoxy) aniline, 4-(4-methoxy phenoxy) aniline,4-(3-methoxyphenoxy) aniline, 4-(2-methoxyphenoxy) aniline,4-(3-phenoxyphenoxy) aniline, 4-(4-phenoxyphenoxy) aniline,4-[4-(trifluoromethyl) phenoxy] aniline, 4-[3-(trifluoromethyl) phenoxy]aniline, 4-[2-(trifluoromethyl) phenoxy] aniline,4-(2-naphthyloxyphenoxy) aniline, 4-(1-naphthyloxyphenoxy) aniline,4-[(1,1′-biphenyl-4-yl)oxy] aniline, 4-(4-nitrophenoxy) aniline,4-(3-nitrophenoxy) aniline, 4-(2-nitrophenoxy) aniline,3-nitro-4-aminophenyl phenyl ether, 2-nitro-4-(4-nitrophenoxy) aniline,4-(2,4-dinitrophenoxy) aniline, 3-nitro-4-phenoxy aniline,4-(2-chlorophenoxy) aniline, 4-(3-chlorophenoxy) aniline,4-(4-chlorophenoxy) aniline, 4-(2,4-dichlorophenoxy) aniline,3-chloro-4-(4-chlorophenoxy) aniline, and 4-(4-chloro-3-tolyloxy)aniline.

Of the epoxy resins useful as [b5] for the present invention, commercialproducts of monofunctional epoxy resins include Denacol® EX-731(glycidylphthalimide, manufactured by Nagase ChemteX Corporation) andOPP-G (o-phenyl phenyl glycidyl ether, manufactured by Sanko Co., Ltd.),and commercial products of di-functional epoxy resinsones include GAN(N-diglycidyl aniline, manufactured by Nippon Kayaku Co., Ltd.) andTOREP® A-204E (diglycidyl-p-phenoxy aniline, manufactured by Toray FineChemicals Co., Ltd.).

The tri- or more functional epoxy resin used as [b6] in the thirdpreferred embodiment according to the present invention is a compoundhaving three or more epoxy groups in one molecule. Examples of [b6]include glycidyl amine epoxy resin, glycidyl ether epoxy resin, andaminophenol epoxy resin.

The compound of [b6] preferably contains 3 to 7, more preferably 3 to 4,functional groups. If there exist too many functional groups, the curedmatrix resin will be so brittle that the impact resistance willdeteriorate in some cases.

Examples of tri- or more functional glycidyl amine epoxy resins includediaminodiphenylmethane type, diaminodiphenyl sulfone type,metaxylenediamine type, 1,3-bisaminomethyl cyclohexane type, andisocyanurate type epoxy resins.

Examples of tri- or more functional glycidyl ether epoxy resins includephenol novolac type, orthocresol novolac type, tris-hydroxyphenylmethane type, and tetraphenylol ethane type epoxy resins.

Furthermore, in addition to the above tri- or more functional glycidylamine epoxy resins and tri- or more functional glycidyl ether epoxyresins, the tri- or more functional epoxy resins also includeaminophenol epoxy resins, which contain both a glycidyl amine group anda glycidyl ether group in one molecule.

Of the tri- or more functional epoxy resins given above,diaminodiphenylmethane type and aminophenol type epoxy resins areparticularly preferred because of a good balance among physicalproperties.

The heat resistance can decrease if the content of [b6] is too smallwhereas the cross-linking density can increase leading to a brittlematerial if the content of [b6] is too large, possibly resulting in acarbon fiber reinforced material suffering from deterioration in impactresistance and strength. Therefore, the content of [b6] in the prepregincluding the preliminary reaction product is preferably 40 to 80 partsby mass, more preferably 45 to 75 parts by mass, and still morepreferably 50 to 70 parts by mass, relative to the total amount, whichrepresents 100 parts by mass, of the component [B] in the prepregincluding the preliminary reaction product.

Commercial products of diaminodiphenyl methane type epoxy resin usefulas [b6] include Sumiepoxy® ELM434 (manufactured by Sumitomo ChemicalCo., Ltd.), Araldite® MY720, Araldite® MY721, Araldite® MY9512,Araldite® MY9663 (all manufactured by Huntsman Advanced Materials Gmbh),and Epotohto® YH-434 (manufactured by Tohto Kasei Co., Ltd.).

Of the preferred epoxy resins other than the epoxy resins used as [b5]or [b6], the di-functional epoxy resins include glycidyl ether typeepoxy resins produced from a phenol as precursor. Examples of such epoxyresins include bisphenol A epoxy resin, bisphenol F epoxy resin, andbisphenol S epoxy resin.

Being low in viscosity, liquid bisphenol A epoxy resins and bisphenol Fepoxy resins are preferably used in combination with other epoxy resins.

Compared to liquid bisphenol A epoxy resins, solid bisphenol A epoxyresins will form a structure with a low cross-linking density, whichwill be low in heat resistance but high in toughness, and accordinglythey are used in combination with a glycidyl amine epoxy resin, liquidbisphenol A epoxy resin, or bisphenol F epoxy resin.

Commercial products of bisphenol A epoxy resin include Epon® 825(manufactured by Japan Epoxy Resins Co., Ltd.), EPICLON® 850(manufactured by DIC), Epotohto® YD-128 (manufactured by Tohto KaseiCo., Ltd.), and D. E. R.® 331 and D. E. R.® 332 (both manufactured byThe Dow Chemical Company).

Commercial products of bisphenol F epoxy resin include jER® 806, jER®807, and jER® 1750 (all manufactured by Japan Epoxy Resins Co., Ltd.),EPICLON® 830 (manufactured by DIC), and Epotohto® YD-170 (manufacturedby Tohto Kasei Co., Ltd.)

Unless there occurs a significant reduction in the heat resistance ormechanical properties, the prepreg according to the present invention ineach preferred embodiment may contain an epoxy compound that correspondsto any of the epoxy compounds other than [b1] and [b2] in the firstpreferred embodiment according to the present invention, an epoxycompound that corresponds to any of the epoxy compounds other than [b3]and [b4] in the second preferred embodiment according to the presentinvention, or an epoxy compound that corresponds to any of the epoxycompounds other than [b5] and [b6] in the third preferred embodimentaccording to the present invention. Useful examples include bisphenol Sepoxy resin, alicyclic epoxy resin, epoxy resin having a biphenylskeleton, epoxy resin having a naphthalene skeleton, epoxy resin havinga dicyclopentadiene skeleton, urethane modified epoxy resin, hydantoinor resorcinol epoxy resin, phenol novolac epoxy resin, cresol novolacepoxy resin, other novolac epoxy resins, and monoepoxy compounds havingonly one epoxy group in one molecule. In each preferred embodiment, theaddition of appropriate ones that correspond to those given above makesit possible to achieve a good balance between mechanical property andheat resistance or realize appropriate adjustment of the resinviscosity.

An epoxy resin with a naphthalene skeleton will give cured resin havingboth a low water absorption percentage and a high heat resistance. Inaddition, biphenyl epoxy resins, dicyclopentadiene epoxy resins, phenolaralkyl epoxy resins, and diphenyl fluorene epoxy resins are alsopreferred because they give cured resin with a low water absorptionpercentage. Urethane modified epoxy resins and isocyanate modified epoxyresins give cured resin with a high fracture toughness and a highelongation percentage.

Commercial products of biphenyl epoxy resin include jER® YX4000(manufactured by Mitsubishi Chemical Corporation).

Commercial products of naphthalene epoxy resin include EPICLON® HP-4032(manufactured by DIC).

Commercial products of dicyclopentadiene epoxy resin include EPICLON®HP-7200 (manufactured by DIC).

Commercial products of meta-xylene diamine epoxy resin include TETRAD-X(manufactured by Mitsubishi Gas Chemical Co., Inc.).

Commercial products of 1,3-bisaminomethyl cyclohexane epoxy resininclude TETRAD-C (manufactured by Mitsubishi Gas Chemical Co., Inc.).

Commercial products of isocyanurate epoxy resin include TEPIC®-P(manufactured by Nissan Chemical Industries, Ltd.).

Commercial products of tris-hydroxyphenyl methane epoxy resin includeTactix® 742 (manufactured by Huntsman Advanced Materials Gmbh).

Commercial products of tetraphenylol ethane epoxy resin include jER®1031S (manufactured by Japan Epoxy Resins Co., Ltd.).

Commercial products of phenol novolac epoxy resin include D.E.N.® 431and D.E.N.® 438 (both manufactured by The Dow Chemical Company) and jER®152 (manufactured by Japan Epoxy Resins Co., Ltd.)

Commercial products of orthocresol novolac epoxy resin include EOCN-1020(manufactured by Nippon Kayaku Co., Ltd.) and EPICLON® N-660(manufactured by DIC).

Commercial products of resorcinol epoxy resin include Denacol® EX-201(manufactured by Nagase ChemteX Corporation).

Commercial products of urethane modified epoxy resin include AER4152(manufactured by Asahi Kasei E-materials Corp.).

Commercial products of hydantoin epoxy resin include AY238 (manufacturedby Huntsman Advanced Materials Gmbh).

Commercial products of phenol aralkyl epoxy resin include NC-3000(manufactured by Nippon Kayaku Co., Ltd.).

The curing agent used as the component [C] for the present invention maybe any compound that has an active group that can react with an epoxyresin under energy irradiation, i.e., exposure to heat, microwave,visible light, infrared light, ultraviolet light, electron beam, orradiation. Examples of such an active group that can react with an epoxyresin include those containing an amino group or an acid anhydridegroup. When using a curing agent for an epoxy resin, the preservationstability of the prepreg that contains it is preferably as high aspossible, and from the viewpoint of allowing the prepreg to have a highpreservation stability, it is preferably solid at 23° C. Here, theexpression “being solid” means that at least either the glass transitiontemperature or the melting point is 23° C. or more and the substancesubstantially does not show fluidity at 23° C.

The component [C] is preferably an aromatic amine compound andpreferably has one to four phenyl groups in the molecule from theviewpoint of heat resistance and mechanical property. Furthermore, sincea bent molecular skeleton can contribute to an increase in the resin'selastic modulus and improvement in mechanical property, the epoxy resincuring agent is more preferably an aromatic polyamine compound in whichat least one phenyl group contained in the backbone has an amino groupat an ortho or meta position. Furthermore, from the viewpoint of heatresistance, an aromatic polyamine compound in which two or more phenylgroups have amino groups at para positions is preferred. Specificexamples of such aromatic polyamine compounds include phenylene diamine,diaminodiphenylmethane, diaminodiphenyl sulfone, meta-xylylene diamine,(p-phenylene methylene) dianiline, various derivatives thereof such asalkyl-substituted derivatives, and various isomers having amino groupsat different positions. To provide materials for spacecraft andaircraft, in particular, the use of 4,4′-diaminodiphenyl sulfone or3,3′-diaminodiphenyl sulfone is preferred because they can give curedproducts having high heat resistance and elastic modulus while hardlysuffering from a decrease in linear expansion coefficient or a reductionin heat resistance due to moisture absorption. These aromatic aminecompounds may be used singly or as a mixture of two or more thereof.When mixed with other components, they may be powder or liquid, orpowdery and liquid aromatic amine compounds may be mixed together.

Usable commercial products of aromatic amine compounds includeSeikacure®-S (manufactured by Seika K.K.), MDA-220 (manufactured byMitsui Chemicals, Inc.), Lonzacure® M-DIPA (manufactured by Lonza),Lonzacure® M-MIPA (manufactured by Lonza), and 3,3′-DAS (manufactured byMitsui Chemicals, Inc.).

When an aromatic amine is used as the component [C], its content ispreferably such that the number of moles of the active hydrogen atoms inthe aromatic amine is 0.6 to 1.2 times, preferably 0.8 to 1.1 times,that of the number of moles of the epoxy groups contained in the epoxyresin in the prepreg from the viewpoint of heat resistance andmechanical property. If it is less than 0.6 times, the resulting curedproduct will fail to have a sufficiently high cross-linking density,leading to a lack of elastic modulus and heat resistance, and theresulting carbon fiber reinforced material will not have good staticstrength characteristics in some cases. If it is more than 1.2 times,the resulting cured material will have an excessively high cross-linkingdensity, which leads to a lack of plastic deformation capacity, and theresulting carbon fiber composite material will possibly be poor inimpact resistance.

In addition to the component [C] in the prepreg according to the presentinvention, an accelerator or a polymerization initiator that isactivated under visible light or ultraviolet light may be added unlessit impairs the heat resistance or heat stability of the epoxy resincomposition. Examples of such an accelerator include tertiary amine,Lewis acid complex, onium salt, imidazole compound, urea compounds,hydrazide compound, and sulfonium salt. The contents of the acceleratorand polymerization initiator have to be adjusted appropriately accordingto the types used, but they are preferably 10 parts by mass or less,preferably 5 parts by mass or less, relative to the total quantity,which accounts for 100 parts by mass, of the epoxy resin. The contentsof an accelerator controlled in this range is preferable because uneventemperature distribution will not occur easily during the molding of acarbon fiber reinforced material in the case where the contents of theaccelerator and polymerization initiator contained are in the aboverange.

It is preferable that the thermoplastic resin used as the component [D]is soluble in the epoxy resin used as the component [B]. It may be athermoplastic resin having a hydrogen bonding functional group becauseit can be expected to have the effect of improving the adhesivenessbetween the resin and carbon fiber. Examples of such a hydrogen bondingfunctional group include alcoholic hydroxyl groups, amide bonds,sulfonyl groups, and carboxyl groups.

The expression “being soluble in an epoxy resin” as used herein meansthat there exists a temperature region where a homogeneous phase isformed as a result of mixing the thermoplastic resin [D] with an epoxyresin and subsequently heating and stirring them. Here, the expression“forming a homogeneous phase” means that there is a state where phaseseparation is not found by visual observation. As long as a homogeneousphase can be formed in a particular temperature range, separation mayoccur in other temperature regions, at 23° C. for example. Dissolutionmay be confirmed by the following method. Specifically, powder of thethermoplastic resin [D] is mixed with an epoxy resin and maintained forseveral hours, for example 2 hours, at a constant temperature that islower than the glass transition temperature of the thermoplastic resin[D] while measuring the viscosity change, and it can be decided that thethermoplastic resin [D] is dissolvable in the epoxy resin if themeasured viscosity is larger by 5% or more than the viscosity of theepoxy resin alone heated at the same constant temperature.

Examples of thermoplastic resins having an alcoholic hydroxyl groupinclude polyvinyl acetal resins such as polyvinyl formal and polyvinylbutyral as well as polyvinyl alcohol and phenoxy resins.

Examples of thermoplastic resins having an amide bond include polyamide,polyimide, polyamideimide, and polyvinyl pyrolidone.

Examples of thermoplastic resins having a sulfonyl group includepolysulfone and polyethersulfone.

Examples of thermoplastic resins having a carboxyl group includepolyester, polyamide, and polyamideimide. The carboxyl group may belocated either or both in the main chain or/and at a chain end.

Of the above ones, polyamides, polyimides, and polysulfones may contain,in their main chains, an ether bond or a functional group such ascarbonyl group. In such polyamide compounds, the nitrogen atom in theamide group may have a substituent.

Commercially available products of the thermoplastic resin that issoluble in epoxy resin resins and at the same time has a hydrogenbonding functional group include polyvinyl acetal resin products such asMowital® (manufactured by Kuraray Co., Ltd.) and Vinylec® K(manufactured by JNC); polyvinyl alcohol resin products such as DenkaPoval® (manufactured by Denka Company Limited); polyamide resin productssuch as Macromelt® (manufactured by Henkel Hakusui Corporation) andAmilan® CM4000 (manufactured by Toray Industries, Inc.); polyimideproducts such as Ultem® (manufactured by SABIC Innovative Plastics IPBV), Aurum registered trademark) (manufactured by Mitsui Chemicals,Inc.), and Vespel® (manufactured by DuPont); PEEK polymers such asVictrex® (manufactured by Victrex PLC); polysulfone products such asUDEL® (manufactured by Solvay Advanced Polymers, L.L.C.); and polyvinylpyrolidone products such as Luviskol® (manufactured by BASF Japan).

Other preferred examples of such a thermoplastic resin soluble in epoxyresin include thermoplastic resins having a polyaryl ether skeleton. Theuse of such a thermoplastic resin having a polyaryl ether skeleton asthe component [D] serves to control the tackiness of the resultingprepreg, control the fluidity of the matrix resin during the thermalcuring of the prepreg, and provide a tough carbon fiber reinforcedmaterial without impairing the heat resistance or elastic modulus.

Examples of a thermoplastic resin having a polyaryl ether skeletoninclude polysulfone, polyphenyl sulfone, polyethersulfone,polyetherimide, polyphenylene ether, polyether ether ketone, andpolyether ether sulfone, and these thermoplastic resins having polyarylether skeletons may be used singly or as a mixture of two or morethereof.

To ensure a high heat resistance, in particular, the thermoplastic resinhaving a polyaryl ether skeleton preferably has a glass transitiontemperature (Tg) of at least 150° C. or more, more preferably 170° C. ormore. If the glass transition temperature of the thermoplastic resinhaving a polyaryl ether skeleton is less than 150° C., moldings producedtherefrom may liable to thermal deformation in some cases.

The functional end group in the thermoplastic resin having a polyarylether skeleton is preferably a hydroxyl group, carboxyl group, thiolgroup, anhydride, etc. because they can react with acation-polymerizable compound. Commercial products of thermoplasticresins having a polyaryl ether skeleton with a functional end groupinclude commercial products of polyethersulfone such as Sumikaexcel®PES3600P, Sumikaexcel® PES5003P, Sumikaexcel® PES5200P, Sumikaexcel®PES7200P (all manufactured by Sumitomo Chemical Co., Ltd.), Virantage®VW-10200RFP, and Virantage® VW-10700RFP (both manufactured by SolvayAdvanced Polymers, L.L.C.); copolymeric oligomers of polyethersulfoneand polyether ether sulfone as described in Published JapaneseTranslation of PCT International Publication JP 2004-506789; andcommercial products of polyetherimide such as Ultem® 1000, Ultem® 1010,and Ultem® 1040 (all manufactured by SABIC). An oligomer as referred toherein is a polymer composed of a finite number, commonly 10 to 100, ofmonomers bonded to each other.

The content of the component [D] is preferably in the range of 5 to 45parts by mass, more preferably in the range of 10 to 40 parts by mass,and still more preferably 15 to 35 parts by mass, relative to the totalquantity, which accounts for 100 parts by mass, of the epoxy resinscontained in the prepreg. If the content of the thermoplastic resin iscontrolled in this range, it ensures a good balance between theviscosity of the epoxy resin composition containing the components [B]to [D] and the mechanical property such as toughness and elongationpercentage of the carbon fiber reinforced material formed by curing thecomposition.

For the present invention, organic particles may be added as component[E] in addition to the components [A] to [D]. As a result of this, theprepreg according to the present invention can be cured into a carbonfiber reinforced material having a high impact resistance. The component[E] may be thermoplastic resin particles, rubber particles, etc.

Good examples of thermoplastic resin particles useful for the presentinvention include particles of the various thermoplastic resins listedpreviously to exemplify the thermoplastic resins that are intended foruse after dissolution in epoxy resins. Among others, polyamide particlesare particularly preferable because they are so high in toughness thatcan provide carbon fiber reinforced materials having high impactresistance. Of the various polyamide particle materials, polyamide 12,polyamide 6, polyamide 11, polyamide 66, polyamide 6/12 copolymer, andpolyamide polymers modified with an epoxy compound into a semi IPNstructure (semi IPN polyamide) as described in Example 1 of JapaneseUnexamined Patent Publication (Kokai) No. HEI 01-104624 can achieveparticularly large adhesive strength to epoxy resins. Here, IPN standsfor interpenetrating polymer network, which is a kind of polymer blend.Cross-linked polymers are used as components of a blend and thedissimilar cross-linked polymers are partially or fully entangled toform a multiple network structure. A semi IPN has a multiple networkstructure formed of cross-linked and straight-chain polymers. Semi IPNthermoplastic resin particles can be produced by, for example,dissolving a thermoplastic resin and a thermosetting resin in a commonsolvent, mixing them uniformly, and performing reprecipitation. The useof particles of an epoxy resin and a semi IPN polyamide serves toprepare a prepreg having a high heat resistance and impact resistance.In regard to the shape of such thermoplastic resin particles, they maybe spherical particles, nonspherical particles, or porous particles, ofwhich spherical particles are preferable because they ensure highviscoelasticity by preventing deterioration in the resin flow propertyand also ensure high impact resistance by eliminating potential startingpoints of stress concentration.

If particles prepared by further adding an epoxy resin are used as thethermoplastic resin particles, it is more preferable because theadhesiveness to the epoxy resin acting as the matrix resin is improvedto provide a carbon fiber reinforced material having improved impactresistance. Useful commercial products of such polyamide particlesformed by further adding an epoxy resin include SP-500, SP-10, TR-1, andTR-2 (all manufactured by Toray Industries, Inc.), and Orgasol® 1002D,Orgasol® 2001UD, Orgasol® 2001EXD, Orgasol® 2002D, Orgasol® 3202D,Orgasol® 3501D, and Orgasol® 3502D (all manufactured by Arkema K.K.).

In regard to the shape of such thermoplastic resin particles, they maybe spherical, nonspherical, porous, needle-like, whisker-like, or flaky,of which spherical particles are preferable because spherical particlesdo not work to reduce the epoxy resin flow property and can maintainhigh carbon fiber impregnating property, and the degree of delaminationcaused by local impact is further reduced in drop impact (or localimpact) test so that, in the case where a stress is applied to thecarbon fiber reinforced material after undergoing the impact, there willbe a decreased number of delamination parts resulting from the localimpact and acting as starting points of destruction attributed to stressconcentration, thereby making it possible to obtain a carbon fiberreinforced material having high impact resistance.

Furthermore, there are some thermoplastic resin particles that have ahigher modification effect because they are not dissolved in the matrixresin during the curing step. The feature that they are not dissolvedduring the curing step is also effective for maintaining fluidity of theresin during the curing step and improving the impregnating property.

The rubber particles to use for the present invention may be of agenerally known natural rubber or synthetic rubber. In particular,crosslinked rubber particles that are insoluble in thermosetting resinsare preferred. If they are insoluble in the thermosetting resin used,the material obtained after curing will have an equivalent degree ofheat resistance compared to cured products of the thermosetting resinfree of the particles. Furthermore, changes in morphology will not occurdepending on the difference in the type or curing conditions of thethermosetting resin and therefore, the cured thermosetting resin willhave stable physical property such as toughness. Useful crosslinkedrubber particles include, for example, particles of a copolymer with oneor a plurality of unsaturated compounds and particles produced throughcopolymerization between one or a plurality of unsaturated compounds andcrosslinkable monomers.

Examples of such unsaturated compounds include aliphatic olefins such asethylene and propylene; aromatic vinyl compounds such as styrene andmethyl styrene; conjugated diene compounds such as butadiene, dimethylbutadiene, isoprene, and chloroprene; unsaturated carboxylates such asmethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate,propyl methacrylate, and butyl methacrylate; and vinyl cyanides such asacrylonitrile. Furthermore, it may also be effective to use a carboxylgroup, epoxy group, hydroxyl group, epoxy resin (amino group, amidegroup) or a compound having a functional group that is reactive with thecuring agent. Useful ones include acrylic acid, glycidylmethacrylate,vinyl phenol, vinyl aniline, and acrylamide.

Useful examples of such crosslinkable monomers include compounds in theform of divinylbenzene, diallylphthalate, ethylene glycoldimethacrylate, etc., having a plurality of polymerizable double bondsin one molecule.

These particles can be produced by various generally known conventionalpolymerization methods including, for example, emulsion polymerizationand suspension polymerization. A typical emulsion polymerization processincludes a step for emulsion polymerization of an unsaturated compound,crosslinkable monomers, etc., in the presence of a radicalpolymerization initiator such as peroxide, a molecular weight adjustorsuch as mercaptan and halogenated hydrocarbon, and an emulsifier, a stepfor adding a reaction terminator to stop the polymerization reactionafter reaching a predetermined degree of polymerization conversion, anda subsequent step for water vapor distillation to remove unreactedmonomers out of the polymerization system, thereby providing a latex ofa copolymer. Water is removed from such a latex obtained by emulsionpolymerization to provide crosslinked rubber particles.

Examples of such crosslinked rubber particles include crosslinkedacrylonitrile butadiene rubber particles, crosslinked styrene butadienerubber particles, acrylic rubber particles, and core shell rubberparticles. Core shell rubber particles are in the form of sphericalpolymer particles in which the central part and the surface part are ofdifferent polymers and may have a simple two-phase structure consistingof a core phase and a single shell phase or a multiple layered structure(multiple core shell rubber particles) having a plurality of shellphases such as, for example, a soft core (located innermost), hardshell, soft shell, and hard shell. Here, a soft phase means a phase ofthe aforementioned rubber whereas a hard one means a phase of a resinother than the rubber.

Specific examples of such crosslinked rubber particles includecommercial products of crosslinked acrylonitrile butadiene rubber (NBR)particles such as XER-91 (manufactured by JSR Corporation) and DuoMod®DP5045 (manufactured by Zeon Corporation). For crosslinked styrenebutadiene rubber (SBR) particles, specific examples include XSK-500(manufactured by JSR Corporation). Specific examples for acrylic rubberparticles include Metabrane® W300A and Metabrane® W450A (bothmanufactured by Mitsubishi Rayon Co., Ltd.), and specific examples forcore shell rubber particles include Stafiloid AC3832 and StafiloidAC3816N (both manufactured by Ganz Chemical Co., Ltd.), Metabrane®KW-4426 (manufactured by Mitsubishi Rayon Co., Ltd.), PARALOID®EXL-2611, PARALOID® EXL-3387, PARALOID (registered trademark) EXL-2655,and PARALOID® EXL-2314 (all manufactured by Rohm and Haas Company), andStafiloid AC-3355, Stafiloid TR-2105, Stafiloid TR-2102, StafiloidTR-2122, Stafiloid IM-101, Stafiloid IM-203, Stafiloid IM-301, andStafiloid IM-401 (all manufactured by Ganz Chemical Co., Ltd.). Thesecrosslinked rubber particles may be of a single material or acombination of particles of two or more materials.

To make a particular interlaminar resin layer tougher selectively in acarbon fiber reinforced material obtained by curing a prepreg accordingto the present invention, it is necessary for the organic particles ofthe component [E] to remain in the interlaminar resin layer, and forthis, the component [E] preferably has a number average particlediameter in the range of 5 to 50 μm, more preferably in the range of 7to 40 μm, and still more preferably in the range of 10 to 30 μm. If thenumber average particle diameter is controlled at 5 μm or more, thecomponent [E] will not enter into bundles of carbon fibers of thecomponent [A] and can remain in the interlaminar resin layer in theresulting carbon fiber reinforced material. If the number averageparticle diameter is controlled at 50 μm or less, on the other hand, thematrix resin layer at the prepreg surface will have an appropriatethickness, thereby allowing the carbon fibers of the component [A] inthe resulting carbon fiber reinforced material to have an appropriatevolume content. Here, the value of number average particle diameter touse herein is determined by observing the component [E] at amagnification of ×200 or more using a laser microscope (ultra-deep color3D profile measuring microscope (VK-9510, manufactured by KeyenceCorporation)), selecting 100 particles at random, measuring the diameterof the circumscribed circle about each particle to represent itsparticle size, and calculating the average.

The epoxy resin composition in a prepreg according to the presentinvention may contain a coupling agent, thermosetting resin particles,or inorganic fillers such as silica gel, carbon black, clay, carbonnanotube, carbon particles, and metal powder, unless they impair theadvantageous effect of the invention. Examples of carbon black includechannel black, thermal black, furnace black, and ketjen black.

For the present invention, the preliminary reaction product as areaction product of the component [B] and the component [C] (hereinaftersimply referred to as preliminary reaction product of [B] and [C]) meansa polymer, i.e. a dimmer or larger compound, formed through reaction andchemical bonding between glycidyl groups in the epoxy resin of thecomponent [B] and active groups in the curing agent of the component[C], and it should be soluble in the epoxy resin of [B].

The preferable range of the molecular weight of the polymer depends onits structure, but commonly a weight-average molecular weight of 10,000or less is preferable from the viewpoint of the speed of dissolution inan epoxy resin. It is more preferably 5,000 or less, and still morepreferably 2,000 or less.

For the preliminary reaction product of [B] and [C], the expression“being soluble in the epoxy resin” as used herein means that thereexists a temperature region where a homogeneous phase is formed as aresult of mixing the preliminary reaction product with an epoxy resinand subsequently heating and stirring them. Here, the expression“forming a homogeneous phase” means that there is a state where phaseseparation is not found by visual observation. As long as a homogeneousphase can be formed in a particular temperature range, separation mayoccur in other temperature regions, at 23° C. for example. Dissolutionmay be confirmed by the following method. Specifically, the preliminaryreaction product is mixed in the epoxy resin at 80° C. while measuringthe changes in viscosity, and it can be decided that the preliminaryreaction product is soluble in the epoxy resin if the measured viscositybecomes larger by 5% or more than the viscosity of the epoxy resinalone.

There are some methods to add an preliminary reaction product of [B] and[C] to a prepreg, including a method in which a prepreg precursorcontaining the components [A] to [D] (which may also contain [E]) issubjected to heat-treatment or energy irradiation using microwave,visible light, infrared light, ultraviolet light, electron beam, orradiation to form a preliminary reaction product in the prepreg, amethod in which an epoxy resin composition containing [B] to [D] (whichmay also contain [E]) is subjected to heat-treatment or energyirradiation to form a preliminary reaction product in the epoxy resincomposition, followed by producing a prepreg from the epoxy resincomposition, and a method in which [B] and [C] are preliminarily curedby heat-treatment or energy irradiation and an epoxy resin compositioncontaining them (which may also contain [D] and/or [E]) is added to anepoxy resin composition containing [B] to [D] (which may also contain[E]), followed by producing a prepreg from the epoxy resin composition.

There are no specific limitations on the method to use for the aboveheat-treatment as long as the glycidyl group in the epoxy resin of thecomponent [B] reacts with the active group in the curing agent of thecomponent [C] to undergo chemical bonding. Examples include a method inwhich the prepreg precursor or the epoxy resin composition is heated byapplying hot air, a method in which a heating roller or a heating plateis pressed to the prepreg precursor or the epoxy resin composition toheat them, a method in which infrared ray or microwave is applied to theprepreg precursor or the epoxy resin composition to heat them. Theapplication of hot air for heating is preferable because of easy controlof the temperature, the use of a noncontact technique to permit a smalllikelihood of deterioration in the quality of the prepreg precursor, andcapability of treating a large quantity of the prepreg precursor or theepoxy resin composition at a time.

Good methods for applying hot air include leaving a rolled prepregprecursor or epoxy resin composition in a heated oven with explosionvent. In the case where the prepreg precursor or the epoxy resincomposition is in a frozen or refrigerated state before theheat-treatment, it is preferable to put it in a hermetically sealed bagetc., leave it in a room at 23° C. and 50% RH to avoid condensation,take it out of the bag etc. after the temperature returns to roomtemperature, and leave it in an oven with explosion vent. Combined useof energy ray is also preferred in order to produce a preliminaryreaction product in a limited portion.

The existence of a preliminary reaction product in a prepreg can bedetermined by performing high performance liquid chromatography (HPLC)to compare chromatograms of extracts from a prepreg specimen observedbefore and after the heat-treatment and examining if the peaks derivedfrom the preliminary reaction product show increases in peak area. Here,in the case where the prepreg does not contain a preliminary reactionproduct before the heat-treatment, it can be determined by examining ifnew peaks appear.

To prepare a specimen for HPLC measurement, the epoxy resin compositionis extracted with acetonitrile from a predetermined quantity of theprepreg. If extraction with acetonitrile is impossible, tetrahydrofuranis used, and if extraction is still impossible, N-methyl-2-pyrrolidoneis used.

Acetonitrile and water are used as eluent for HPLC measurement. Ifmeasurement is impossible when acetonitrile and water are used as eluentfor HPLC, tetrahydrofuran and water are used, and if measurement isstill impossible, N-methyl-2-pyrrolidone and water are used.

Regarding the detector to use for HPLC, an appropriate one may beselected from generally known detectors including ultraviolet-visiblespectroscopy (UV/Vis) detector, fluorescent detector, differentialrefraction (RI) detector, and evaporative light scattering detector.

The quantity of the preliminary reaction product required to achieve aparticular value of G′ for the present invention depends on thecomponents of the epoxy resin composition and therefore, may be adjustedappropriately.

To determine the mass ratio among the epoxy resin components of thecomponent [B] in a prepreg that includes a preliminary reaction product,the epoxy resin composition is extracted with deuterated dimethylformamide from a predetermined quantity of the prepreg to prepare aspecimen and subjected to 1H-NMR measurement.

If measurement is impossible with deuterated dimethyl formamide,deuterated tetrahydrofuran is used, and if measurement is stillimpossible, deuterated hexafluoro-2-propanol is used to performed themeasurement.

If it is difficult to calculate the mass ratio from 1H-NMR measurementsalone, generally known analysis methods such as gas chromatography andgas chromatography-mass spectroscopy analysis may be used appropriatelyin combination.

If the tackiness of the prepreg is sufficiently reduced, the adhesion ofthe epoxy resin composition in the prepreg to the guide roll will besufficiently improved and at the same time will ensure high drapability.To realize this effect, at least one surface resin in the prepregaccording to the present invention should have a G′ value in the rangeof 1.0×10³ to 2.0×10⁸ Pa as measured at a temperature of 40° C. and anangular frequency in the range of 0.06 to 314 rad/s. It is preferably inthe range of 2.0×10³ to 2.0×10⁷ Pa, and more preferably in the range of4.0×10³ to 4.0×10⁶ Pa. If the G′ value is smaller than 1.0×10³ Pa, therewill be a larger deposit of the epoxy resin composition on the guideroll when performing the AFP method, leading to a high cleaningfrequency and a decreased productivity and in addition, an excessivetackiness will occur due to a low G′ value to cause a deterioration inresticking work efficiency and sinking of the resin, leading to ashortening of the period in which a required tackiness is maintained(occasionally referred to as tackiness life). If it is larger than2.0×10⁸ Pa, resin powder will occur on the surface of the slit tape asit suffers from abrasion on the guide roll and cleaning will benecessary to remove the resin powder that comes off, thereby causing notonly a decrease in productivity, but also a deterioration in drapabilityand a decrease in handleability.

For the present invention, the term “surface resin” refers to the epoxyresin composition present in the region extending from the prepregsurface to a depth equal to 20% of the thickness of the prepreg.

The G′ value of a surface resin in a prepreg as measured at atemperature of 40° C. and an angular frequency in the range of 0.06 to314 rad/s as referred to herein is determined by taking measurementsusing a dynamic viscoelasticity measuring apparatus (for example ARES,manufactured by TA Instruments) equipped with parallel plates under theconditions of a measuring temperature of 40° C., a parallel plate gap of1 mm, a strain of 0.5%, and an angular frequency in the range of 0.06rad/s to 314 rad/s to give a G′ curve and reading G′ values at differentfrequencies.

In the case where only one surface of the prepreg comes in contact withthe guide roll during the automatic lamination step performed by the AFPmethod, at least the surface resin at that surface should meet therequirements for G′ to allow the prepreg to have required processabilityand handleability, whereas in the case where both surfaces come incontact with the guide roll, it is preferable for the two surface resinslocated at both surfaces to meet the requirements for G′.

Simultaneous achievement of both required processability andhandleability can be realized more easily when one surface and the othersurface of the prepreg differ in the storage elastic modulus G′ of theprepreg surface resin measured at a temperature of 40° C. and an angularfrequency in the range of 0.06 to 314 rad/s. If the two surfaces havenearly the same degree of drapability, the prepreg can have higherprocessability when the prepreg surface resins at the surfaces havedifferent G′ values than in the case where they have the same G′ value.

When only one of the surface resins of the prepreg meets therequirements for G′ to allow the prepreg to have both requiredprocessability and handleability, the unwinding property of the slittape can be improved by attaching a cover film to the other surface.

For the prepreg according to the present invention, it is preferablethat the epoxy resin composition, that is, the remainder of the prepregdeprived of the component [A], has a glass transition temperature in therange of −5° C. to 20° C. as measured by differential scanningcalorimetry (DSC). It is more preferably in the range of 5° C. to 15°C., still more preferably in the range of 7° C. to 13° C. If the glasstransition temperature is in the range, it will be easier to meet therequirements for G′ to allow the prepreg to have both requiredprocessability and handleability.

Here, to determine the glass transition temperature as referred toherein, a DSC curve is obtained by placing a specimen in a nitrogenatmosphere in a DSC apparatus (for example DSC Q-2000, manufactured byTA Instruments), maintaining it at −50° C. for 1 minute, then heating itonce over the temperature range up to 300° C. under the conditions of anaverage temperature ramp rate of 5° C./min, a modulation cycle of 40seconds, and a modulation amplitude of ±0.5° C., and according toJIS-K7121 (1987), straight lines were extended from the baseline towardthe low temperature side and the high temperature side, followed bydetermining the temperature at the point where the straight line that isequidistant in the vertical axis direction from the aforementionedstraight lines and the step-like portion of the glass transition curveintersect each other.

Here, to draw a DSC curve, measurements taken by differential scanningcalorimetry are plotted on a graph in which the vertical axis representsthe difference between the heat energy inputs required by a specimen anda reference in a unit period of time when they are maintained at thesame temperature whereas the horizontal axis represents the temperature.

For the prepreg according to the present invention, the degree ofconversion of the epoxy resin composition, that is, the remainder of theprepreg deprived of the component [A], is preferably 20% or less. It ismore preferably 16% or less, and still more preferably 12% or less.Here, the lower limit is preferably 1% or more. It is more preferably 2or more, and still more preferably 3% or more. A degree of conversion inthis range is preferable because it makes it easier to meet therequirements for G′ to allow the prepreg to have both requiredprocessability and handleability, and sufficiently large adhesivenessbetween laminated prepreg layers will be achieved, thereby reducing thevoid generation that can result from air captured between prepreglayers, in the carbon fiber reinforced material obtained finally.

Here, the degree of conversion of an epoxy resin composition as referredto herein is calculated as described below. First, prepregs are heatedat 100° C. for 1 hour, 2 hours, or 3 hours. Then, for these prepregs,the mass ratio W (preliminary reaction product/unreacted epoxy resincomposition) between the preliminary reaction product and the unreactedepoxy resin composition is calculated by a generally known analysismethod. Subsequently, from each heated prepreg, a DSC curve is obtainedby placing it in a nitrogen atmosphere in a DSC apparatus, maintainingit at 30° C. for 1 minute, then heating it once over the temperaturerange up to 350° C. under the conditions of an average temperature ramprate of 5° C./min, a modulation cycle of 40 seconds, and a modulationamplitude of ±0.5° C., and the exothermic peak is integrated tocalculate the total calorific value per unit mass of each prepreg, whichis defined as QC. Then, a graph is plotted representing W on the X axisand QC on the Y axis and the intercept of the approximate straight lineis defined as QB. Subsequently, from an unheated prepreg, a DSC curve isobtained by placing it in a nitrogen atmosphere in a DSC apparatus,maintaining it at 30° C. for 1 minute, then heating it once over thetemperature range up to 350° C. under the conditions of an averagetemperature ramp rate of 5° C./min, a modulation cycle of 40 seconds,and a modulation amplitude of ±0.5° C., and the exothermic peak isintegrated to calculate the total calorific value per unit mass of eachprepreg, which is defined as QA, followed by calculating the degree ofconversion (%) of the epoxy resin composition as (QB−QA)/QB×100.

The generally known analysis methods useful for calculating the massratio W include HPLC and thermal decomposition gas chromatography-massspectrometry.

For example, prepregs are heated at 100° C. for 1 hour, 2 hours, or 3hours and treated with acetonitrile to extract the epoxy resincomposition to provide specimens for measurement, which were subjectedto HPLC using acetonitrile and water as eluent to separate the unreactedepoxy resin composition and the preliminary reaction product, followedby calculating the mass ratio W (preliminary reaction product/unreactedepoxy resin composition) between the preliminary reaction product andthe unreacted epoxy resin composition for each prepreg.

To distinguish the peak of the preliminary reaction product, the prepregused above for specimen preparation is heated at 100° C. for 1 hour andthe prepreg is treated with acetonitrile to extract the epoxy resincomposition to provide a specimen for measurement, which is thensubjected to HPLC measurement, followed by making a comparison betweenthe chromatogram obtained above and a chromatogram of an extract takenfrom the original prepreg to identify an additional peak.

If extraction with acetonitrile is impossible, tetrahydrofuran is used,and if extraction is still impossible, N-methyl-2-pyrrolidone is used.

If measurement is impossible when acetonitrile and water are used aseluent for HPLC, tetrahydrofuran and water are used, and if measurementis still impossible, N-methyl-2-pyrrolidone and water are used.

Regarding the detector to use for HPLC, an appropriate one may beselected from generally known detectors including ultraviolet-visiblespectroscopy (UV/Vis) detector, fluorescent detector, differentialrefraction (RI) detector, and evaporative light scattering detector.

The prepreg and the prepreg precursor according to the present inventionare composites of an epoxy resin composition and carbon fibers. Theprepreg and the prepreg precursor according to the present invention areproduced by the hot-melt process to ensure the development of theadvantageous effect of the invention. The hot-melt process is asolvent-free technique designed for the impregnation of carbon fiberswith an epoxy resin composition that is heated beforehand to decreaseits viscosity. The hot-melt process can be carried out by some differentprocedures including a procedure in which a matrix resin heatedbeforehand to decrease the viscosity is used for direct impregnation ofcarbon fibers and a procedure in which release paper sheets laid withresin film are prepared by coating release paper sheets with a matrixresin and then used to sandwich a carbon fiber sheet, followed byapplying heat and pressure to ensure the impregnation of the carbonfiber sheet with the matrix resin. The above procedures are generallyintended to provide sheet-like prepregs and prepreg precursors, but acarbon fiber strand may be directly immersed in a resin compositionhaving a decreased viscosity to provide tape-like or thread-likeprepregs or prepreg precursors. The temperature and time for carryingout the hot-melt process may be controlled appropriately to allow thepreparation of a prepreg while simultaneously performing preliminaryreaction of the resin, or a prepreg precursor may be prepared withoutarresting the reaction of the resin, followed by performing theaforementioned treatment for preliminary reaction of a sheet-likeprepreg precursor or a tape-like one intended for processing by anautomatic lamination machine as described later. It is preferable thatpreliminary reaction is started after the preparation of a prepregprecursor from the viewpoint of permitting local control of theviscoelasticity.

For the prepreg according to the present invention, the carbon fibersheet preferably has an areal weight of 100 to 1,000 g/m². If the arealweight of the carbon fiber sheet is less than 100 g/m², a larger numberof sheets have to be stacked to ensure a required thickness when moldinga carbon fiber reinforced material, possibly leading to troublesomelamination operation. If it is more than 1,000 g/m², on the other hand,the prepreg tends to be low in drapability. On the other hand, fibermass content is preferably 40 to 90 mass %, and more preferably 50 to 80mass %. This is preferable because void generation is depressed duringmolding and good mechanical property of the carbon fiber is developed.Depending on the molding process, this is also preferable because theheat generation from curing of the resin can be controlled during themolding of large-type members to permit the production of uniformmoldings.

Regarding the structure of the prepreg according to the presentinvention, it may be either a unidirectional prepreg or a woven fabricprepreg.

The prepreg according to the present invention can be processed into atape or a thread as it is cut to a required width by a generally knownmethod. Such tape-like or thread-like prepregs can be applied suitableto an automatic lamination machine.

Such cutting of a prepreg can be achieved by using a generally knowncutter. Examples include cemented carbide blade cutter, ultrasoniccutter, and round blade cutter.

The carbon fiber reinforced material according to the present inventioncan be produced by laminating sheets of the prepreg according to thepresent invention in an appropriate form and heating them to cure theresin. It is preferable to press them during the molding step from theviewpoint of depressing the formation of voids and obtaining uniformlycured products. Here, the application of heat and pressure can becarried out by using a generally known method such as autoclave molding,press molding, bagging molding, wrapping tape molding, and internalpressure molding.

Carbon fiber reinforced materials produced by the above molding methodspreferably have glass transition temperatures in the range of 100° C. to250° C. from the viewpoint of processability of the molded materials inpost-treatment steps. In the case of aircraft members, in particular,the glass transition temperature is preferably in the range of 170° C.to 250° C. in order to permit their application to members for use athigh temperatures.

EXAMPLES

The present invention will now be illustrated in detail with referenceto Examples, but it should be understood that the invention is notconstrued as being limited thereto. Preparation and evaluation ofprepreg samples in Examples were performed in an atmosphere under theconditions of a temperature of 25° C.±2° C., a relative humidity of 50%,and the use of one measurement (n=1) unless otherwise specified.

Component [A]<Carbon Fiber>

-   -   Torayca® T800S-24K-10E (carbon fiber with 24,000 filaments,        tensile strength of 5.9 GPa, tensile modulus of 290 GPa, and        tensile elongation of 2.0%, manufactured by Toray Industries,        Inc.).

Component [B]<Epoxy Resin>

[Aminophenol Epoxy Resin: Corresponding to Epoxy Resins [b1], [b3], and[b6]]

-   -   Araldite® MY0600 (triglycidyl-m-aminophenol, manufactured by        Huntsman Advanced Materials Gmbh, epoxy equivalent weight 105)    -   jER® 630 (triglycidyl-p-aminophenol, manufactured by Mitsubishi        Chemical Corporation, epoxy equivalent weight 100)

[Glycidyl Ether Epoxy Resin: Corresponding to Epoxy Resins [b2] and[b4]]

-   -   jER® 819 (bisphenol A epoxy resin, manufactured by Mitsubishi        Chemical Corporation, epoxy equivalent weight 200)    -   jER® 825 (bisphenol A epoxy resin, manufactured by Mitsubishi        Chemical Corporation, epoxy equivalent weight 175)    -   jER® 1055 (bisphenol A epoxy resin, manufactured by Mitsubishi        Chemical Corporation, epoxy equivalent weight 850)    -   jER® 807 (bisphenol F epoxy resin, manufactured by Mitsubishi        Chemical Corporation, epoxy equivalent weight 170)

[Glycidyl Amine Epoxy Resin: Corresponding to Epoxy Resins [b2] and[b6]]

-   -   Sumiepoxy® ELM434 (tetraglycidyl diaminodiphenyl methane,        manufactured by Sumitomo Chemical Co., Ltd., epoxy equivalent        weight 120 g/eq)

[Epoxy Resin Containing One or More Ring Structures Having Four- orMore-Membered Ring and at the Same Time Containing at Least One AmineType Glycidyl Group or Ether Type Glycidyl Group Directly Connected to aRing Structure: Corresponding to Epoxy Resins [b2] and [b5]]

-   -   Denacol® EX-731 (N-glycidylphthalimide, manufactured by Nagase        ChemteX Corporation)    -   GAN (N-diglycidyl aniline, manufactured by Nippon Kayaku Co.,        Ltd.)    -   TOREP® A-204E (diglycidyl-N-phenoxy aniline, manufactured by        Toray Fine Chemicals Co., Ltd.)

[Other Epoxy Resins]

-   -   EPICLON® HP-7200 (dicyclopentadiene epoxy resin, manufactured by        DIC Corporation, epoxy equivalent weight 265)    -   jER® YX4000 (biphenyl epoxy resin, manufactured by Mitsubishi        Chemical Corporation, epoxy equivalent weight 186)    -   EPICLON® HP-4032 (naphthalene epoxy resin, manufactured by DIC        Corporation, epoxy equivalent weight 150) Component [C]<curing        agent>    -   Seikacure S (4,4′-diaminodiphenyl sulfone, manufactured by Seika        K.K., active hydrogen equivalent weight: 62)    -   3,3′-DAS (3,3′-diaminodiphenyl sulfone, manufactured by Mitsui        Fine Chemical, Inc., active hydrogen equivalent weight: 62)

Component [D]<Thermoplastic Resin>

-   -   Sumikaexcel® PES5003P (hydroxyl-capped polyethersulfone,        manufactured by Sumitomo Chemical Co., Ltd., Tg 225° C.)    -   Virantage® VW-10700RP (hydroxyl-capped polyethersulfone,        manufactured by Solvay Advanced Polymers, Tg 220° C.)

Component [E]<Organic Particles>

-   -   Orgasol® 1002D Nat 1 (polyamide 6 particles, manufactured by        Arkema, number average particle diameter 20 μm)

(1) Preparation of Epoxy Resin Composition

In a kneader, an epoxy resin for the component [B] and a thermoplasticresin for the component [D] are added according to the lists ofcomponents and proportions given in Tables 1 to 13, heated up to 160° C.while kneading, and stirred for 1 hour so that the component [D] isdissolved to provide a transparent viscous liquid. This was allowed tocool to 70° C. while kneading and then a curing agent for the component[C] was added, followed by additional kneading to provide an epoxy resincomposition 1.

In the case where organic particles for the component [E] were used, thecomponent [E] was added and kneaded before adding the component [C], andsubsequently the component [C] was added, followed by kneading toprovide an epoxy resin composition 2 that contained the component [E].

(2) Measurement of Storage Elastic Modulus G′ of Surface Resin

The storage elastic modulus G′ of a surface resin was determined bytaking measurements using a dynamic viscoelasticity measuring apparatus(manufactured by TA Instruments) equipped with parallel plates withdiameter of 8 mm under the conditions of a measuring temperature of 40°C., a parallel plate gap of 1 mm, a strain of 0.5%, and an angularfrequency in the range of 0.06 rad/s to 314 rad/s. To show typicalmeasurements, G′ values determined at an angular frequency of 0.06rad/s, 6.28 rad/s, or 314 rad/s are given in Tables 14 to 26.

(3) Preparation of Prepreg Precursor

For the following Examples, prepreg precursors were prepared asdescribed below. Silicone was spread over a piece of release paper andthe epoxy resin composition 1 or 2 prepared in paragraph (1) was spreaduniformly on top of it to prepare a resin film 1 and a resin film 2. Alayer of uniformly paralleled carbon fibers (T800S-24K-10E, manufacturedby Toray Industries, Inc.) was sandwiched between two sheets of theresin film 1 and heated and pressed using press rolls to provide animpregnated first prepreg (carbon fiber mass 190 g/cm², resin content21%) that contained carbon fibers impregnated with the epoxy resincomposition 1. After the impregnation with the epoxy resin composition1, the two pieces of release paper were removed from the impregnatedfirst prepreg. Subsequently, the impregnated first prepreg wassandwiched between two sheets of the resin film 1 or 2 and heated andpressed using press rolls to provide a prepreg precursor (carbon fibermass 190 g/cm², resin content 35%) impregnated with the epoxy resincomposition 1 or 2.

(4) Measurement of Glass Transition Temperature of Epoxy ResinComposition in Prepreg

After preparing a prepreg specimen of about 10 mg, a DSC curve wasobtained by placing the specimen in a nitrogen atmosphere in a DSCapparatus (DSC Q-2000, manufactured by TA Instruments), maintaining itat −50° C. for 1 minute, then heating it once over the temperature rangeup to 300° C. under the conditions of an average temperature ramp rateof 5° C./min, a modulation cycle of 40 seconds, and a modulationamplitude of ±0.5° C., and according to JIS-K7121 (1987), straight lineswere extended from the baseline toward the low temperature side and thehigh temperature side, followed by determining the temperature at thepoint where the straight line that is equidistant in the vertical axisdirection from the aforementioned straight lines and the step-likeportion of the glass transition curve intersect each other to determinethe glass transition temperature.

To draw a DSC curve as referred to herein, measurements taken bydifferential scanning calorimetry are plotted on a graph in which thevertical axis represents the difference between the heat energy inputsrequired by a specimen and a reference in a unit period of time whenthey are maintained at the same temperature whereas the horizontal axisrepresents the temperature.

(5) Heat-Treatment of Prepreg Precursor

In an oven with explosion vent (SPHH-102, manufactured by Espec Corp.)having an interior temperature of 60° C., a roll of the prepregprecursor was placed and heated in an air atmosphere for a predeterminedperiod. After the heat-treatment, the prepreg was taken out of the oven,and put in a polyethylene bag, which was hermetically sealed and left tostand in a room at 23° C. and 50% RH until it cooled to roomtemperature. In the case where the prepreg precursor was in a frozen orrefrigerated state before the heat-treatment, it was put in ahermetically sealed bag etc., left in a room at 23° C. and 50% RH, takenout of the bag etc. after the temperature returned to room temperature,and placed in the oven.

(6) Confirmation of Existence of Preliminary Reaction Product in Prepreg

High performance liquid chromatography (HPLC, manufactured by Waters)was performed using acetonitrile and water as eluent in order to confirmthe existence of a preliminary reaction product of [B] and [C] in theprepreg. A prepreg sample of a predetermined quantity was treated withacetonitrile to extract the epoxy resin composition to provide aspecimen for measurement, which is then subjected to measurement using amodel 2695 separation module manufactured by Waters, a model 2487 UVdetector manufactured by Waters, and a Nuclesoil column 4.0×250 mmmanufactured by GL Sciences, Inc. under the conditions of a flow rate of1.5 mL/min, an injection rate of 10 μL, and a detection wavelength of230 nm. The existence of the preliminary reaction product was determinedby comparing chromatograms of epoxy resin extracts observed before andafter the heat-treatment and examining if the peaks derived from thepreliminary reaction product showed increases in peak area.

(7) Calculation of Mass Ratio Among Constituents of Component [B] inPrepreg Including Preliminary Reaction Product

A prepreg sample of a predetermined quantity was treated with deuterateddimethyl formamide to extract the epoxy resin composition to provide aspecimen for measurement, which is then subjected to 1H-NMR analysis(JNM-AL400, manufactured by JEOL Ltd.) using deuterated dimethylformamide as solvent to determine the mass ratio among the constituentsof the component [B].

(8) Measurement of Degree of Conversion of Epoxy Resin Composition inPrepreg

First, prepregs or resin films were heated at 100° C. for 1 hour, 2hours, or 3 hours. An epoxy resin composition extracted withacetonitrile from a prepreg or a resin film was used as specimen formeasurement, which was subjected to HPLC (the apparatus used forevaluation in (6)) using acetonitrile and water as eluent to separatethe unreacted epoxy resin composition and the preliminary reactionproduct, followed by calculating the mass ratio W (preliminary reactionproduct/unreacted epoxy resin composition) between the preliminaryreaction product and the unreacted epoxy resin composition for eachprepreg. Subsequently, a specimen of about 10 mg or about 5 mg was takenfrom a heated prepreg or resin film prepared above and a DSC curve isobtained by placing it in a nitrogen atmosphere in a DSC apparatus (theapparatus used for evaluation in (4)), maintaining it at 30° C. for 1minute, then heating it once over the temperature range up to 350° C.under the conditions of an average temperature ramp rate of 5° C./min, amodulation cycle of 40 seconds, and a modulation amplitude of ±0.5° C.,and the exothermic peak was integrated to calculate the total calorificvalue per unit mass of each prepreg. Then, a graph was plottedrepresenting W on the X axis and the total calorific value per unit massof the prepreg on the Y axis and the intercept of the approximatestraight line was defined as QB. In addition, a specimen of about 10 mgor about 5 mg was taken from an unheated prepreg or resin film preparedabove and a DSC curve was obtained by placing it in a nitrogenatmosphere in a DSC apparatus, maintaining it at 30° C. for 1 minute,then heating it once over the temperature range up to 350° C. under theconditions of an average temperature ramp rate of 5° C./min, amodulation cycle of 40 seconds, and a modulation amplitude of ±0.5° C.,and the exothermic peak was integrated to calculate the total calorificvalue per unit mass of the prepreg, which was defined as QA, followed bycalculating the degree of conversion (%) of the epoxy resin compositionas (QB−QA)/QB×100.

(9) Measurement of Tackiness Between Prepreg and Metal (Prepreg's DryProperty Evaluation)

To determine the tackiness between prepreg and metal, a 10 mm×10 mmaluminum plate attached to the weight of a portable tackiness tester(manufactured by Imada Co., Ltd.) with a piece of double-side tape andpressed against the surface of a prepreg specimen with a load of 0.5 kgfor 0.1 second, and then it was pulled up at a speed 100 mm/min whilemeasuring the required force. The measurement was performed in anenvironment at a temperature of 25° C. and a humidity of 50 RH %. Fordry property, a prepreg was evaluated according to the measuredtackiness and rated in five stages from A to E. A specimen was rated asA when the tackiness was 0.0 N, B when it was in the range of 0.1 to 0.2N, C when it was in the range of 0.3 to 0.4 N, D when it was in therange of 0.5 to 0.9 N, and E when it was 1.0 N or more. Thus, A means“excellent” in terms of dry property, whereas E means “poor” and thespecimen was outside the allowable range in terms of dry property.

(10) Evaluation of Prepreg for Drapability

A specimen with a width of 12.7 mm and a length of 400 mm was cut out ofa prepreg and one end thereof was fixed on a horizontal table in such amanner that a 200 mm end portion of the prepreg specimen protruded fromthe edge of the table. After leaving it to stand for 10 minutes, thedeflection angle of the prepreg specimen was measured to represent itsdrapability. In this instance, the deflection angle means the anglebetween the straight line formed by extending the prepreg specimen fixedon the table in the horizontal direction and the straight line formed byconnecting the free end of the prepreg specimen to the starting end ofthe protruded portion of the prepreg specimen. The drapability of aprepreg was evaluated according to the measured deflection angle andrated in five stages from A to E. A specimen was rated as A when thedeflection angle was 31° or more, B when it was in the range of 25° to30°, C when it was in the range of 19° to 24°, D when it was in therange of 10° to 18°, and E when it was 9° or less. Thus, A means“excellent” in terms of drapability, whereas E means “poor” and thespecimen was outside the allowable range in terms of drapability.

(11) Overall Evaluation

For either dry property or drapability, a prepreg was given 5 pointswhen rated as A, 4 points when rated as B, 3 points when rated as C, 2points when rated as D, and 1 point when rated as E, and for overallevaluation, a prepreg was rated as A when it gains an average of 4.5points or more over the two characteristics evaluation items, B whengaining 4 points or more, C when gaining 3.5 points or more, D whengaining 3 points or more, and E if it was rated as E for eithercharacteristics evaluation item.

(12) Curing of Prepreg

Sheets of 100 mm×100 mm were cut out of a unidirectional prepreg and tenof them were laminated in one direction, subjected to vacuum bagmolding, and cured in an autoclave for 2 hours at a temperature of 180°C. and a pressure of 6 kg/cm², thereby providing a plate with athickness of about 2 mm of an unidirectional carbon fiber reinforcedmaterial.

(13) Glass Transition Temperature of Carbon Fiber Reinforced Material

A test piece with a length of 55 mm and a width of 12.7 mm is cut out ofthe plate prepared in (12) above and subjected to dynamic torsionmeasurement (DMA measurement) in the temperature range of 40° C. to 300°C. using a dynamic viscoelasticity measuring apparatus (ARES) under theconditions of a torsion vibration frequency of 6.28 rad/s, generatedtorque of 3.0×10⁻⁴ to 2.0×10⁻² N m, and heating rate of 5.0° C./min,thereby determining the G′ value in the temperature range of 50° C. to290° C. In the resulting temperature-storage elastic modulus curve, theglass transition temperature is defined as the temperature representedby the intersection between the baseline in the lower temperature partof the curve and the largest-gradient tangent to that part of the curvewhere the storage elastic modulus G′ sharply changes.

(14) Definition of 0° Direction of Carbon Fiber Reinforced Material

As specified in JIS K7017 (1999), the fiber direction of aunidirectional carbon fiber reinforced material is defined as its axisdirection and the axis direction is defined as the 0° direction whereasthe direction perpendicular to the axis is defined as the 90° direction.

(15) Measurement of 0° Tensile Strength of Carbon Fiber ReinforcedMaterial

Sheets of a specified size were cut out of a unidirectional prepreg andsix of them were laminated in one direction, subjected to vacuum bagmolding, and cured in an autoclave for 2 hours at a temperature of 180°C. and a pressure of 6 kg/cm², thereby providing a unidirectional carbonfiber reinforced material (unidirectional reinforced material). A tabwas bonded to this unidirectional reinforced material as specified inASTM D3039-00 and a rectangular part with a length of 254 mm and a widthof 12.7 mm was cut out to provide a test piece with its length directionbeing the 0° direction of the reinforced material. The resulting 0°directional tensile test piece was subjected to tensile test in a −60°C. environment according to ASTM D3039-00 using a universal testingmachine (Instron ® 5565 P8564, manufactured by Instron Japan Co., Ltd.)at a testing rate of 1.27 mm/min. Five test pieces were examined (n=5).

(16) Electron Microscopic Observation of Carbon Fiber ReinforcedMaterial (Observation for Existence of Phase-Separated Structure)

A thin section was cut out of the carbon fiber reinforced materialprepared above, stained, and observed by a transmission electronmicroscope (H-7100, manufactured by Hitachi, Ltd.) at an acceleratingvoltage 100 kV to obtain a transmission electron image of an appropriatemagnification, which was then used to check for a phase-separatedstructure. As the stain, either OsO₄ or RuO₄ that was suitable for theresin composition was used to ensure a required contrast to permit easymorphological examination. The above-mentioned appropriate magnificationmeans 50,000 times for a structural period of 1 nm or more and less than10 nm, 20,000 times for a structural period of 10 nm or more and lessthan 100 nm, 2,000 times for a structural period of 100 nm or more andless than 1,000 nm, and 1,000 times for a structural period of 1,000 nmor more.

TABLE 1 Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- ple 1 ple 2 ple3 ple 4 ple 5 ple 6 ple 7 ple 8 Epoxy resin Component [B] aminophenolepoxy resin composition triglycidyl-m-aminophenol (Araldite ®MY600)triglycidyl-p-aminophenol (jER ®630) 50 50 50 50 50 50 50 50 Component[B] glycidyl ether epoxy resin bisphenol A epoxy resin (jER ®819)bisphenol A epoxy resin (jER ®825) bisphenol A epoxy resin (jER ®1055)bisphenol F epoxy resin (jER ®807) 50 50 50 50 50 50 50 50 Component [B]glycidyl amine epoxy resin tetraglycidyl diaminodiphenylmethane(Sumiepoxy ®ELM434) Component [B] epoxy resin that contains one or morering structures having four- or more-membered ring and at the same timecontaining at least one amine type glycidyl group or ether type glycidylgroup directly connected to a ring structure N-glycidylphthalimide(Denacol ®EX-731) N-diglycidyl aniline (GAN) N,N-diglycidyl-4-phenoxyaniline (TOREP ®A-204E) Component [B] other epoxy resindicyclopentadiene type epoxy (EPICLON ®HP-7200) biphenyl type epoxy(jER ®YX4000) naphthalene epoxy resin (EPICLON ®HP-4032) Component [C]aromatic amine type curing agent 4,4′-diaminodiphenyl sulfone (SeikacureS) 35 35 35 35 35 35 35 35 3,3′-diaminodiphenyl sulfone (3,3′-DAS)Component [D] thermoplastic resin polyethersulfone(Sumikaexcel ®PES5003P) polyethersulfone (Virantage ®VW-10700RP) 35 3535 35 35 35 35 35 Component [E] organic particles polyamide 6 particles(Orgasol ® 1002D Nat 1) 25 25 25 25 25 25 25 25 Heat treatment time(hours) 60 90 120 145 170 only only one one one side 90 side 60 side 90opposite side 60

TABLE 2 Example 9 Example 10 Example 11 Example 12 Example 13 Epoxyresin Component [B] aminophenol epoxy resin compositiontriglycidyl-m-aminophenol (Araldite ®MY600) triglycidyl-p-aminophenol(jER ®630) 10 10 10 50 50 Component [B] glycidyl ether epoxy resinbisphenol A epoxy resin (jER ®819) bisphenol A epoxy resin (jER ®825)bisphenol A epoxy resin (jER ®1055) bisphenol F epoxy resin (jER ®807)30 30 30 Component [B] glycidyl amine epoxy resin tetraglycidyldiaminodiphenylmethane 60 60 60 50 50 (Sumiepoxy ®ELM434) Component [B]epoxy resin that contains one or more ring structures having four- ormore-membered ring and at the same time containing at least one aminetype glycidyl group or ether type glycidyl group directly connected to aring structure N-glycidylphthalimide (Denacol ®EX-731) N-diglycidylaniline (GAN) N,N-diglycidyl-4-phenoxy aniline (TOREP ®A-204E) Component[B] other epoxy resin dicyclopentadiene type epoxy (EPICLON ®HP-7200)biphenyl type epoxy (jER ®YX4000) naphthalene epoxy resin(EPICLON ®HP-4032) Component [C] aromatic amine type curing agent4,4′-diaminodiphenyl sulfone (Seikacure S) 35 35 35 5 53,3′-diaminodiphenyl sulfone (3,3′-DAS) 40 40 Component [D]thermoplastic resin polyethersulfone (Sumikaexcel ®PES5003P) 20 20 20 1515 polyethersulfone (Virantage ®VW-10700RP) Component [E] organicparticles polyamide 6 particles (Orgasol ® 1002D Nat 1) 20 20 20 Heattreatment time (hours) 60 90 120 90 120 Example 14 Example 15 Example 16Example 17 Epoxy resin Component [B] aminophenol epoxy resin compositiontriglycidyl-m-aminophenol 50 50 50 (Araldite ®MY600)triglycidyl-p-aminophenol (jER ®630) 50 Component [B] glycidyl etherepoxy resin bisphenol A epoxy resin (jER ®819) bisphenol A epoxy resin(jER ®825) 50 50 50 bisphenol A epoxy resin (jER ®1055) bisphenol Fepoxy resin (jER ®807) Component [B] glycidyl amine epoxy resintetraglycidyl diaminodiphenylmethane 50 (Sumiepoxy ®ELM434) Component[B] epoxy resin that contains one or more ring structures having four-or more-membered ring and at the same time containing at least one aminetype glycidyl group or ether type glycidyl group directly connected to aring structure N-glycidylphthalimide (Denacol ®EX-731) N-diglycidylaniline (GAN) N,N-diglycidyl-4-phenoxy aniline (TOREP ®A-204E) Component[B] other epoxy resin dicyclopentadiene type epoxy (EPICLON ®HP-7200)biphenyl type epoxy (jER ®YX4000) naphthalene epoxy resin(EPICLON ®HP-4032) Component [C] aromatic amine type curing agent4,4′-diaminodiphenyl sulfone (Seikacure S) 5 3,3′-diaminodiphenylsulfone (3,3′-DAS) 40 35 35 35 Component [D] thermoplastic resinpolyethersulfone (Sumikaexcel ®PES5003P) 15 polyethersulfone(Virantage ®VW-10700RP) 35 35 35 Component [E] organic particlespolyamide 6 particles (Orgasol ® 1002D Nat 1) 25 25 25 Heat treatmenttime (hours) 145 90 120 145

TABLE 3 Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- ple 18 ple 19ple 20 ple 21 ple 22 ple 23 ple 24 ple 25 Epoxy resin Component [B]aminophenol epoxy resin composition triglycidyl-m-aminophenol 50 50 50(Araldite ®MY600) triglycidyl-p-aminophenol (jER ®630) 50 50 50 50 50Component [B] glycidyl ether epoxy resin bisphenol A epoxy resin(jER ®819) bisphenol A epoxy resin (jER ®825) 50 50 50 bisphenol A epoxyresin (jER ®1055) bisphenol F epoxy resin (jER ®807) 50 50 50 50 50Component [B] glycidyl amine epoxy resin tetraglycidyldiaminodiphenylmethane (Sumiepoxy ®ELM434) Component [B] epoxy resinthat contains one or more ring structures having four- or more-memberedring and at the same time containing at least one amine type glycidylgroup or ether type glycidyl group directly connected to a ringstructure N-glycidylphthalimide (Denacol ®EX-731) N-diglycidyl aniline(GAN) N,N-diglycidyl-4-phenoxy aniline (TOREP ®A-204E) Component [B]other epoxy resin dicyclopentadiene type epoxy (EPICLON ®HP-7200)biphenyl type epoxy (jER ®YX4000) naphthalene epoxy resin(EPICLON ®HP-4032) Component [C] aromatic amine type curing agent4,4′-diaminodiphenyl sulfone (Seikacure S) 20 20 20 20 203,3′-diaminodiphenyl sulfone (3,3′-DAS) 20 20 20 Component [D]thermoplastic resin polyethersulfone (Sumikaexcel ®PES5003P) 20 20 20 2020 20 20 20 polyethersulfone (Virantage ®VW-10700RP) 45 45 45 45 45 4545 45 Component [E] organic particles polyamide 6 particles (Orgasol ®1002D Nat 1) Heat treatment time (hours) 30 60 90 115 140 60 90 115

TABLE 4 Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- ple 26 ple 27ple 28 ple 29 ple 30 ple 31 ple 32 ple 33 Epoxy resin Component [B]aminophenol epoxy resin composition triglycidyl-m-aminophenol(Araldite ®MY600) triglycidyl-p-aminophenol (jER ®630) 50 50 50Component [B] glycidyl ether epoxy resin bisphenol A epoxy resin(jER ®819) bisphenol A epoxy resin (jER ®825) 15 15 15 15 15 bisphenol Aepoxy resin (jER ®1055) bisphenol F epoxy resin (jER ®807) 50 50 50Component [B] glycidyl amine epoxy resin tetraglycidyldiaminodiphenylmethane 60 60 60 60 60 (Sumiepoxy ®ELM434) Component [B]epoxy resin that contains one or more ring structures having four- ormore-membered ring and at the same time containing at least one aminetype glycidyl group or ether type glycidyl group directly connected to aring structure N-glycidylphthalimide (Denacol ®EX-731) 25 25 25 25 25N-diglycidyl aniline (GAN) N,N-diglycidyl-4-phenoxy aniline(TOREP ®A-204E) Component [B] other epoxy resin dicyclopentadiene typeepoxy (EPICLON ®HP-7200) biphenyl type epoxy (jER ®YX4000) naphthaleneepoxy resin (EPICLON ®HP-4032) Component [C] aromatic amine type curingagent 4,4′-diaminodiphenyl sulfone (Seikacure S) 20 20 20 40 40 40 40 403,3′-diaminodiphenyl sulfone (3,3′-DAS) Component [D] thermoplasticresin polyethersulfone (Sumikaexcel ®PES5003P) 20 20 20 10 10 10 10 10polyethersulfone (Virantage ®VW-10700RP) 45 45 45 Component [E] organicparticles polyamide 6 particles (Orgasol ® 1002D Nat 1) 20 20 20 20 20Heat treatment time (hours) only only one 30 75 150 only only one oneside 60 one one side 30 side 60 opposite side 30 side 75 side 30

TABLE 5 Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- ple 34 ple 35ple 36 ple 37 ple 38 ple 39 ple 40 ple 41 Epoxy resin Component [B]aminophenol epoxy resin composition triglycidyl-m-aminophenol(Araldite ®MY600) triglycidyl-p-aminophenol (jER ®630) Component [B]glycidyl ether epoxy resin bisphenol A epoxy resin (jER ®819) bisphenolA epoxy resin (jER ®825) 15 35 30 15 15 30 bisphenol A epoxy resin(jER ®1055) bisphenol F epoxy resin (jER ®807) Component [B] glycidylamine epoxy resin tetraglycidyl diaminodiphenylmethane 60 60 60 60 60 4570 80 (Sumiepoxy ®ELM434) Component [B] epoxy resin that contains one ormore ring structures having four- or more-membered ring and at the sametime containing at least one amine type glycidyl group or ether typeglycidyl group directly connected to a ring structureN-glycidylphthalimide (Denacol ®EX-731) 25 5 10 25 25 25 30 20N-diglycidyl aniline (GAN) N,N-diglycidyl-4-phenoxy aniline(TOREP ®A-204E) Component [B] other epoxy resin dicyclopentadiene typeepoxy (EPICLON ®HP-7200) biphenyl type epoxy (jER ®YX4000) naphthaleneepoxy resin (EPICLON ®HP-4032) Component [C] aromatic amine type curingagent 4,4′-diaminodiphenyl sulfone (Seikacure S) 40 40 40 40 40 40 44 443,3′-diaminodiphenyl sulfone (3,3′-DAS) Component [D] thermoplasticresin polyethersulfone (Sumikaexcel ®PES5003P) 10 10 10 15 20 10 10 10polyethersulfone (Virantage ®VW-10700RP) Component [E] organic particlespolyamide 6 particles (Orgasol ® 1002D Nat 1) 20 20 20 20 20 20 20 20Heat treatment time (hours) one 75 75 75 75 75 75 75 side 75 oppositeside 30

TABLE 6 Exam- Exam- Exam- EExam- Exam- Exam- Exam- Exam- ple 42 ple 43ple 44 ple 45 ple 46 ple 47 ple 48 ple 49 Epoxy resin Component [B]aminophenol epoxy resin composition triglycidyl-m-aminophenol(Araldite ®MY600) triglycidyl-p-aminophenol (jER ®630) Component [B]glycidyl ether epoxy resin bisphenol A epoxy resin (jER ®819) bisphenolA epoxy resin (jER ®825) 10 10 10 10 10 10 35 20 bisphenol A epoxy resin(jER ®1055) bisphenol F epoxy resin (jER ®807) Component [B] glycidylamine epoxy resin tetraglycidyl diaminodiphenylmethane 60 60 60 60 60 6060 60 (Sumiepoxy ®ELM434) Component [B] epoxy resin that contains one ormore ring structures having four- or more-membered ring and at the sametime containing at least one amine type glycidyl group or ether typeglycidyl group directly connected to a ring structureN-glycidylphthalimide (Denacol ®EX-731) N-diglycidyl aniline (GAN) 30 3030 30 30 30 5 20 N,N-diglycidyl-4-phenoxy aniline (TOREP ®A-204E)Component [B] other epoxy resin dicyclopentadiene type epoxy(EPICLON ®HP-7200) biphenyl type epoxy (jER ®YX4000) naphthalene epoxyresin (EPICLON ®HP-4032) Component [C] aromatic amine type curing agent4,4′-diaminodiphenyl sulfone (Seikacure S) 45 45 45 45 45 45 45 453,3′-diaminodiphenyl sulfone (3,3′-DAS) Component [D] thermoplasticresin polyethersulfone (Sumikaexcel ®PES5003P) 10 10 10 10 10 10 10 10polyethersulfone (Virantage ®VW-10700RP) Component [E] organic particlespolyamide 6 particles (Orgasol ® 1002D Nat 1) 20 20 20 20 20 20 20 20Heat treatment time (hours) 30 75 150 only only one 75 75 one one side75 side 30 side 75 opposite side 30

TABLE 7 Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- ple 50 ple 51ple 52 ple 53 ple 54 ple 55 ple 56 ple 57 Epoxy resin Component [B]aminophenol epoxy resin composition triglycidyl-m-aminophenol(Araldite ®MY600) triglycidyl-p-aminophenol (jER ®630) Component [B]glycidyl ether epoxy resin bisphenol A epoxy resin (jER ®819) bisphenolA epoxy resin (jER ®825) 10 10 30 bisphenol A epoxy resin (jER ®1055)bisphenol F epoxy resin (jER ®807) Component [B] glycidyl amine epoxyresin tetraglycidyl diaminodiphenylmethane 60 60 40 60 80 60 60 60(Sumiepoxy ®ELM434) Component [B] epoxy resin that contains one or morering structures having four- or more-membered ring and at the same timecontaining at least one amine type glycidyl group or ether type glycidylgroup directly connected to a ring structure N-glycidylphthalimide(Denacol ®EX-731) N-diglycidyl aniline (GAN) 30 30 30 40 20N,N-diglycidyl-4-phenoxy aniline 40 40 40 (TOREP ®A-204E) Component [B]other epoxy resin dicyclopentadiene type epoxy (EPICLON ®HP-7200)biphenyl type epoxy (jER ®YX4000) naphthalene epoxy resin(EPICLON ®HP-4032) Component [C] aromatic amine type curing agent4,4′-diaminodiphenyl sulfone (Seikacure S) 45 45 38 50 503,3′-diaminodiphenyl sulfone (3,3′-DAS) 45 45 45 Component [D]thermoplastic resin polyethersulfone (Sumikaexcel ®PES5003P) 15 20 10 1010 10 10 10 polyethersulfone (Virantage ®VW-10700RP) Component [E]organic particles polyamide 6 particles (Orgasol ® 1002D Nat 1) 20 20 2020 20 20 20 20 Heat treatment time (hours) 75 75 75 75 75 20 50 100

TABLE 8 Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- ple 58 ple 59ple 60 ple 61 ple 62 ple 63 ple 64 ple 65 Epoxy resin Component [B]aminophenol epoxy resin composition triglycidyl-m-aminophenol(Araldite ®MY600) triglycidyl-p-aminophenol (jER ®630) Component [B]glycidyl ether epoxy resin bisphenol A epoxy resin (jER ®819) bisphenolA epoxy resin (jER ®825) 35 15 20 bisphenol A epoxy resin (jER ®1055)bisphenol F epoxy resin (jER ®807) Component [B] glycidyl amine epoxyresin tetraglycidyl diaminodiphenylmethane 60 60 60 60 60 60 60 40(Sumiepoxy ®ELM434) Component [B] epoxy resin that contains one or morering structures having four- or more-membered ring and at the same timecontaining at least one amine type glycidyl group or ether type glycidylgroup directly connected to a ring structure N-glycidylphthalimide(Denacol ®EX-731) N-diglycidyl aniline (GAN) N,N-diglycidyl-4-phenoxyaniline 40 40 40 5 25 40 40 40 (TOREP ®A-204E) Component [B] other epoxyresin dicyclopentadiene type epoxy (EPICLON ®HP-7200) biphenyl typeepoxy (jER ®YX4000) naphthalene epoxy resin (EPICLON ®HP-4032) Component[C] aromatic amine type curing agent 4,4′-diaminodiphenyl sulfone(Seikacure S) 3,3′-diaminodiphenyl sulfone (3,3′-DAS) 45 45 45 45 45 4545 38 Component [D] thermoplastic resin polyethersulfone(Sumikaexcel ®PES5003P) 10 10 10 10 10 15 20 10 polyethersulfone(Virantage ®VW-10700RP) Component [E] organic particles polyamide 6particles (Orgasol ® 1002D Nat 1) 20 20 20 20 20 20 20 20 Heat treatmenttime (hours) only only one 50 50 50 50 50 one one side 50 side 20 side50 opposite side 20

TABLE 9 Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- ple 66 ple 67ple 68 ple 69 ple 70 ple 71 ple 72 ple 73 Epoxy resin Component [B]aminophenol epoxy resin composition triglycidyl-m-aminophenol(Araldite ®MY600) triglycidyl-p-aminophenol (jER ®630) Component [B]glycidyl ether epoxy resin bisphenol A epoxy resin (jER ®819) bisphenolA epoxy resin (jER ®825) bisphenol A epoxy resin (jER ®1055) bisphenol Fepoxy resin (jER ®807) Component [B] glycidyl amine epoxy resintetraglycidyl diaminodiphenylmethane 50 40 70 90 70 90 70 90(Sumiepoxy ®ELM434) Component [B] epoxy resin that contains one or morering structures having four- or more-membered ring and at the same timecontaining at least one amine type glycidyl group or ether type glycidylgroup directly connected to a ring structure N-glycidylphthalimide(Denacol ®EX-731) N-diglycidyl aniline (GAN) N,N-diglycidyl-4-phenoxyaniline 50 60 (TOREP ®A-204E) Component [B] other epoxy resindicyclopentadiene type epoxy (EPICLON ®HP-7200) 30 10 biphenyl typeepoxy (jER ®YX4000) 30 10 naphthalene epoxy resin (EPICLON ®HP-4032) 3010 Component [C] aromatic amine type curing agent 4,4′-diaminodiphenylsulfone (Seikacure S) 45 45 45 45 55 55 3,3′-diaminodiphenyl sulfone(3,3′-DAS) 45 41 Component [D] thermoplastic resin polyethersulfone(Sumikaexcel ®PES5003P) 10 10 polyethersulfone (Virantage ®VW-10700RP)20 20 20 20 20 20 Component [E] organic particles polyamide 6 particles(Orgasol ® 1002D Nat 1) 20 20 20 20 20 20 20 20 Heat treatment time(hours) 50 50 75 75 75 75 60 60

TABLE 10 Comparative Comparative Comparative Comparative Comparativeexample 1 example 2 example 3 example 4 example 5 Epoxy resin Component[B] aminophenol epoxy resin composition triglycidyl-m-aminophenol(Araldite ®MY600) triglycidyl-p-aminophenol (jER ®630) 50 50 10 10 50Component [B] glycidyl ether epoxy resin bisphenol A epoxy resin(jER ®819) bisphenol A epoxy resin (jER ®825) bisphenol A epoxy resin(jER ®1055) bisphenol F epoxy resin (jER ®807) 50 50 30 30 Component [B]glycidyl amine epoxy resin tetraglycidyl diaminodiphenylmethane(Sumiepoxy ®ELM434) 60 60 50 Component [B] epoxy resin that contains oneor more ring structures having four- or more-membered ring and at thesame time containing at least one amine type glycidyl group or ethertype glycidyl group directly connected to a ring structureN-glycidylphthalimide (Denacol ®EX-731) N-diglycidyl aniline (GAN)N,N-diglycidyl-4-phenoxy aniline (TOREP ®A-204E) Component [B] otherepoxy resin dicyclopentadiene type epoxy (EPICLON ®HP-7200) biphenyltype epoxy (jER ®YX4000) naphthalene epoxy resin (EPICLON ®HP-4032)Component [C] aromatic amine type curing agent 4,4′-diaminodiphenylsulfone (Seikacure S) 35 35 35 35 5 3,3′-diaminodiphenyl sulfone(3,3′-DAS) 40 Component [D] thermoplastic resin polyethersulfone(Sumikaexcel ®PES5003P) 20 20 15 polyethersulfone(Virantage ®VW-10700RP) 35 35 Component [E] organic particles polyamide6 particles (Orgasol ® 1002D Nat 1) 25 25 20 20 Heat treatment time(hours) 0 190 0 170 0 Comparative Comparative Comparative example 6example 7 example 8 Epoxy resin Component [B] aminophenol epoxy resincomposition triglycidyl-m-aminophenol (Araldite ®MY600)triglycidyl-p-aminophenol (jER ®630) 50 50 80 Component [B] glycidylether epoxy resin bisphenol A epoxy resin (jER ®819) bisphenol A epoxyresin (jER ®825) bisphenol A epoxy resin (jER ®1055) 50 20 bisphenol Fepoxy resin (jER ®807) Component [B] glycidyl amine epoxy resintetraglycidyl diaminodiphenylmethane (Sumiepoxy ®ELM434) 50 Component[B] epoxy resin that contains one or more ring structures having four-or more-membered ring and at the same time containing at least one aminetype glycidyl group or ether type glycidyl group directly connected to aring structure N-glycidylphthalimide (Denacol ®EX-731) N-diglycidylaniline (GAN) N,N-diglycidyl-4-phenoxy aniline (TOREP ®A-204E) Component[B] other epoxy resin dicyclopentadiene type epoxy (EPICLON ®HP-7200)biphenyl type epoxy (jER ®YX4000) naphthalene epoxy resin(EPICLON ®HP-4032) Component [C] aromatic amine type curing agent4,4′-diaminodiphenyl sulfone (Seikacure S) 5 35 35 3,3′-diaminodiphenylsulfone (3,3′-DAS) 40 Component [D] thermoplastic resin polyethersulfone(Sumikaexcel ®PES5003P) 15 polyethersulfone (Virantage ®VW-10700RP) 3535 Component [E] organic particles polyamide 6 particles (Orgasol ®1002D Nat 1) 25 25 Heat treatment time (hours) 190 0 0

TABLE 11 Comparative Comparative Comparative Comparative Comparativeexample 9 example 10 example 11 example 12 example 13 Epoxy resinComponent [B] aminophenol epoxy resin compositiontriglycidyl-m-aminophenol (Araldite ®MY600) triglycidyl-p-aminophenol(jER ®630) 50 50 50 70 Component [B] glycidyl ether epoxy resinbisphenol A epoxy resin (jER ®819) bisphenol A epoxy resin (jER ®825) 15bisphenol A epoxy resin (jER ®1055) 50 30 bisphenol F epoxy resin(jER ®807) 50 50 Component [B] glycidyl amine epoxy resin tetraglycidyldiaminodiphenylmethane (Sumiepoxy ®ELM434) 60 Component [B] epoxy resinthat contains one or more ring structures having four- or more-memberedring and at the same time containing at least one amine type glycidylgroup or ether type glycidyl group directly connected to a ringstructure N-glycidylphthalimide (Denacol ®EX-731) 25 N-diglycidylaniline (GAN) N,N-diglycidyl-4-phenoxy aniline (TOREP ®A-204E) Component[B] other epoxy resin dicyclopentadiene type epoxy (EPICLON ®HP-7200)biphenyl type epoxy (jER ®YX4000) naphthalene epoxy resin(EPICLON ®HP-4032) Component [C] aromatic amine type curing agent4,4′-diaminodiphenyl sulfone (Seikacure S) 20 20 20 20 403,3′-diaminodiphenyl sulfone (3,3′-DAS) Component [D] thermoplasticresin polyethersulfone (Sumikaexcel ®PES5003P) 20 20 20 20 10polyethersulfone (Virantage ®VW-10700RP) 45 45 45 45 Component [E]organic particles polyamide 6 particles (Orgasol ® 1002D Nat 1) 20 Heattreatment time (hours) 0 90 0 0 0 Comparative Comparative ComparativeComparative example 14 example 15 example 16 example 17 Epoxy resinComponent [B] aminophenol epoxy resin compositiontriglycidyl-m-aminophenol (Araldite ®MY600) triglycidyl-p-aminophenol(jER ®630) Component [B] glycidyl ether epoxy resin bisphenol A epoxyresin (jER ®819) bisphenol A epoxy resin (jER ®825) 15 10 10 bisphenol Aepoxy resin (jER ®1055) bisphenol F epoxy resin (jER ®807) Component [B]glycidyl amine epoxy resin tetraglycidyl diaminodiphenylmethane(Sumiepoxy ®ELM434) 60 60 60 60 Component [B] epoxy resin that containsone or more ring structures having four- or more-membered ring and atthe same time containing at least one amine type glycidyl group or ethertype glycidyl group directly connected to a ring structureN-glycidylphthalimide (Denacol ®EX-731) 25 N-diglycidyl aniline (GAN) 3030 N,N-diglycidyl-4-phenoxy aniline (TOREP ®A-204E) 40 Component [B]other epoxy resin dicyclopentadiene type epoxy (EPICLON ®HP-7200)biphenyl type epoxy (jER ®YX4000) naphthalene epoxy resin(EPICLON ®HP-4032) Component [C] aromatic amine type curing agent4,4′-diaminodiphenyl sulfone (Seikacure S) 40 45 45 3,3′-diaminodiphenylsulfone (3,3′-DAS) 45 Component [D] thermoplastic resin polyethersulfone(Sumikaexcel ®PES5003P) 10 10 10 10 polyethersulfone(Virantage ®VW-10700RP) Component [E] organic particles polyamide 6particles (Orgasol ® 1002D Nat 1) 20 20 20 20 Heat treatment time(hours) 250 0 250 0

TABLE 12 Comparative Comparative Comparative Comparative Comparativeexample 18 example 19 example 20 example 21 example 22 Epoxy resinComponent [B] aminophenol epoxy resin compositiontriglycidyl-m-aminophenol (Araldite ®MY600) triglycidyl-p-aminophenol(jER ®630) Component [B] glycidyl ether epoxy resin bisphenol A epoxyresin (jER ®819) bisphenol A epoxy resin (jER ®825) bisphenol A epoxyresin (jER ®1055) 20 20 20 bisphenol F epoxy resin (jER ®807) Component[B] glycidyl amine epoxy resin tetraglycidyl diaminodiphenylmethane(Sumiepoxy ®ELM434) 60 60 60 60 70 Component [B] epoxy resin thatcontains one or more ring structures having four- or more-membered ringand at the same time containing at least one amine type glycidyl groupor ether type glycidyl group directly connected to a ring structureN-glycidylphthalimide (Denacol ®EX-731) 20 N-diglycidyl aniline (GAN) 20N,N-diglycidyl-4-phenoxy aniline (TOREP ®A-204E) 40 20 Component [B]other epoxy resin dicyclopentadiene type epoxy (EPICLON ®HP-7200) 30biphenyl type epoxy (jER ®YX4000) naphthalene epoxy resin(EPICLON ®HP-4032) Component [C] aromatic amine type curing agent4,4′-diaminodiphenyl sulfone (Seikacure S) 40 45 45 3,3′-diaminodiphenylsulfone (3,3′-DAS) 45 45 Component [D] thermoplastic resinpolyethersulfone (Sumikaexcel ®PES5003P) 10 10 10 10 polyethersulfone(Virantage ®VW-10700RP) 20 Component [E] organic particles polyamide 6particles (Orgasol ® 1002D Nat 1) 20 20 20 20 20 Heat treatment time(hours) 250 0 0 0 0 Comparative Comparative Comparative Comparativeexample 23 example 24 example 25 example 26 Epoxy resin Component [B]aminophenol epoxy resin composition triglycidyl-m-aminophenol(Araldite ®MY600) triglycidyl-p-aminophenol (jER ®630) Component [B]glycidyl ether epoxy resin bisphenol A epoxy resin (jER ®819) bisphenolA epoxy resin (jER ®825) bisphenol A epoxy resin (jER ®1055) bisphenol Fepoxy resin (jER ®807) Component [B] glycidyl amine epoxy resintetraglycidyl diaminodiphenylmethane (Sumiepoxy ®ELM434) 70 70 70 70Component [B] epoxy resin that contains one or more ring structureshaving four- or more-membered ring and at the same time containing atleast one amine type glycidyl group or ether type glycidyl groupdirectly connected to a ring structure N-glycidylphthalimide(Denacol ®EX-731) N-diglycidyl aniline (GAN) N,N-diglycidyl-4-phenoxyaniline (TOREP ®A-204E) Component [B] other epoxy resindicyclopentadiene type epoxy (EPICLON ®HP-7200) 30 biphenyl type epoxy(jER ®YX4000) 30 30 naphthalene epoxy resin (EPICLON ®HP-4032) 30Component [C] aromatic amine type curing agent 4,4′-diaminodiphenylsulfone (Seikacure S) 45 45 45 55 3,3′-diaminodiphenyl sulfone(3,3′-DAS) Component [D] thermoplastic resin polyethersulfone(Sumikaexcel ®PES5003P) polyethersulfone (Virantage ®VW-10700RP) 20 2020 20 Component [E] organic particles polyamide 6 particles (Orgasol ®1002D Nat 1) 20 20 20 20 Heat treatment time (hours) 200 0 200 0

TABLE 13 Comparative Comparative Comparative Comparative Comparativeexample 27 example 28 example 29 example 30 example 31 Epoxy resinComponent [B] aminophenol epoxy resin compositiontriglycidyl-m-aminophenol (Araldite ®MY600) triglycidyl-p-aminophenol(jER ®630) Component [B] glycidyl ether epoxy resin bisphenol A epoxyresin (jER ®819) bisphenol A epoxy resin (jER ®825) bisphenol A epoxyresin (jER ®1055) 20 20 20 40 bisphenol F epoxy resin (jER ®807)Component [B] glycidyl amine epoxy resin tetraglycidyldiaminodiphenylmethane (Sumiepoxy ®ELM434) 70 80 80 80 60 Component [B]epoxy resin that contains one or more ring structures having four- ormore-membered ring and at the same time containing at least one aminetype glycidyl group or ether type glycidyl group directly connected to aring structure N-glycidylphthalimide (Denacol ®EX-731) N-diglycidylaniline (GAN) N,N-diglycidyl-4-phenoxy aniline (TOREP ®A-204E) Component[B] other epoxy resin dicyclopentadiene type epoxy (EPICLON ®HP-7200)biphenyl type epoxy (jER ®YX4000) naphthalene epoxy resin(EPICLON ®HP-4032) 30 Component [C] aromatic amine type curing agent4,4′-diaminodiphenyl sulfone (Seikacure S) 55 30 30 30 303,3′-diaminodiphenyl sulfone (3,3′-DAS) Component [D] thermoplasticresin polyethersulfone (Sumikaexcel ®PES5003P) 14 11 16 14polyethersulfone (Virantage ®VW-10700RP) 20 Component [E] organicparticles polyamide 6 particles (Orgasol ® 1002D Nat 1) 20 20 20 20 20Heat treatment time (hours) 160 0 0 0 0 Comparative ComparativeComparative example 32 example 33 example 34 Epoxy resin Component [B]aminophenol epoxy resin composition triglycidyl-m-aminophenol(Araldite ®MY600) triglycidyl-p-aminophenol (jER ®630) Component [B]glycidyl ether epoxy resin bisphenol A epoxy resin (jER ®819) bisphenolA epoxy resin (jER ®825) 20 50 50 bisphenol A epoxy resin (jER ®1055)bisphenol F epoxy resin (jER ®807) Component [B] glycidyl amine epoxyresin tetraglycidyl diaminodiphenylmethane (Sumiepoxy ®ELM434) 80 50 50Component [B] epoxy resin that contains one or more ring structureshaving four- or more-membered ring and at the same time containing atleast one amine type glycidyl group or ether type glycidyl groupdirectly connected to a ring structure N-glycidylphthalimide(Denacol ®EX-731) N-diglycidyl aniline (GAN) N,N-diglycidyl-4-phenoxyaniline (TOREP ®A-204E) Component [B] other epoxy resindicyclopentadiene type epoxy (EPICLON ®HP-7200) biphenyl type epoxy(jER ®YX4000) naphthalene epoxy resin (EPICLON ®HP-4032) Component [C]aromatic amine type curing agent 4,4′-diaminodiphenyl sulfone (SeikacureS) 30 30 30 3,3′-diaminodiphenyl sulfone (3,3′-DAS) Component [D]thermoplastic resin polyethersulfone (Sumikaexcel ®PES5003P) 14polyethersulfone (Virantage ®VW-10700RP) Component [E] organic particlespolyamide 6 particles (Orgasol ® 1002D Nat 1) 20 Heat treatment time(hours) 0 190 240

TABLE 14 Example Example Example Example 1 2 3 4 Characteristics storageelastic modulus G′ of 40° C., 0.06 rad/s 2.1 × 10³ 6.7 × 10³ 1.3 × 10⁴3.3 × 10⁴ of prepreg surface resin (Pa) 40° C., 6.28 rad/s 5.2 × 10⁴ 9.2× 10⁴ 2.6 × 10⁵ 5.2 × 10⁵ 40° C., 314 rad/s 1.2 × 10⁶ 2.0 × 10⁶ 5.6 ×10⁶ 2.4 × 10⁷ storage elastic modulus G′ of 40° C., 0.06 rad/s same onsame on same on same on opposite-side surface resin (Pa) 40° C., 6.28rad/s both sides both sides both sides both sides 40° C., 314 rad/sglass transition temperature of prepreg (° C.) 5.2 10.1 14.6 19.4 degreeof conversion of epoxy resin composition (%) 5.7 7.9 9.7 11.8 tackinessbetween prepreg and tackiness value (N) 0.2 0.0 0.0 0.0 metal (25° C.)acceptable A B C D E rejectable B A A A drapability (25° C.) deflectionangle 30 25 20 1 acceptable A B C D E rejectable B B C D overallevaluation acceptable A B C D E rejectable B A B C Characteristics glasstransition temperature of cured product (° C.) 200 200 200 200 of curedproduct phase-separated structure absent absent absent absent tensilestrength (MPa) — — — — Example Example Example Example 5 6 7 8Characteristics storage elastic modulus G′ of 40° C., 0.06 rad/s 2.3 ×10⁵ 2.1 × 10³ 6.7 × 10³ 6.7 × 10³ of prepreg surface resin (Pa) 40° C.,6.28 rad/s 1.2 × 10⁷ 5.2 × 10⁴ 9.2 × 10⁴ 9.2 × 10⁴ 40° C., 314 rad/s 1.6× 10⁸ 1.2 × 10⁶ 2.0 × 10⁶ 2.0 × 10⁶ storage elastic modulus G′ of 40°C., 0.06 rad/s same on 2.0 × 10¹ 2.0 × 10¹ 2.1 × 10³ opposite-sidesurface resin (Pa) 40° C., 6.28 rad/s both sides 1.2 × 10³ 1.2 × 10³ 5.2× 10⁴ 40° C., 314 rad/s 3.5 × 10⁴ 3.5 × 10⁴ 1.2 × 10⁶ glass transitiontemperature of prepreg (° C.) 28.8 −1.4 1.5 7.5 degree of conversion ofepoxy resin composition (%) 15.2 3.5 4.9 6.9 tackiness between prepregand tackiness value (N) 0.0 0.2 0.0 0.0 metal (25° C.) acceptable A B CD E rejectable A B A A drapability (25° C.) deflection angle 10 34 30 25acceptable A B C D E rejectable D A B B overall evaluation acceptable AB C D E rejectable C A A A Characteristics glass transition temperatureof cured product (° C.) 200 200 200 200 of cured product phase-separatedstructure absent absent absent absent tensile strength (MPa) — — — —

TABLE 15 Example Example Example Example Example 9 10 11 12 13Characteristics storage elastic modulus G′ of 40° C., 0.06 rad/s 7.0 ×10³ 1.7 × 10⁴ 2.6 × 10⁴ 6.2 × 10³ 8.8 × 10³ of prepreg surface resin(Pa) 40° C., 6.28 rad/s 1.0 × 10⁵ 1.0 × 10⁵ 5.3 × 10⁵ 8.8 × 10⁴ 2.4 ×10⁵ 40° C., 314 rad/s 2.3 × 10⁶ 7.0 × 10⁶ 4.1 × 10⁷ 1.6 × 10⁶ 6.8 × 10⁶storage elastic modulus G′ of 40° C., 0.06 rad/s same on same on same onsame on same on opposite-side surface resin (Pa) 40° C., 6.28 rad/s bothsides both sides both sides both sides both sides 40° C., 314 rad/sglass transition temperature of prepreg (° C.) 9.8 13.7 19.1 9.5 14.1degree of conversion of epoxy resin composition (%) 5.1 7.4 10.5 8.510.4 tackiness between prepreg and tackiness value (N) 0.0 0.0 0.0 0.00.0 metal (25° C.) acceptable A B C D E rejectable A A A A A drapability(25° C.) deflection angle 26 19 14 25 20 acceptable A B C D E rejectableB C D B C overall evaluation acceptable A B C D E rejectable A B C A BCharacteristics glass transition temperature of cured product (° C.) 205205 205 190 190 of cured product phase-separated structure absent absentabsent absent absent tensile strength (MPa) — — — — — Example ExampleExample Example 14 15 16 17 Characteristics storage elastic modulus G′of 40° C., 0.06 rad/s 2.3 × 10⁴ 6.1 × 10³ 8.0 × 10³ 2.8 × 10⁴ of prepregsurface resin (Pa) 40° C., 6.28 rad/s 5.1 × 10⁵ 8.7 × 10⁴ 2.1 × 10⁵ 4.7× 10⁵ 40° C., 314 rad/s 3.8 × 10⁷ 1.5 × 10⁶ 5.1 × 10⁶ 2.1 × 10⁷ storageelastic modulus G′ of 40° C., 0.06 rad/s same on same on same on same onopposite-side surface resin (Pa) 40° C., 6.28 rad/s both sides bothsides both sides both sides 40° C., 314 rad/s glass transitiontemperature of prepreg (° C.) 18.8 8.8 13.1 17.5 degree of conversion ofepoxy resin composition (%) 12.1 7.2 9.3 11.4 tackiness between prepregand tackiness value (N) 0.0 0.0 0.0 0.0 metal (25° C.) acceptable A B CD E rejectable A A A A drapability (25° C.) deflection angle 16 26 21 16acceptable A B C D E rejectable D B C D overall evaluation acceptable AB C D E rejectable C A B C Characteristics glass transition temperatureof cured product (° C.) 190 185 185 185 of cured product phase-separatedstructure absent absent absent absent tensile strength (MPa) — — — —

TABLE 16 Example Example Example Example 18 19 20 21 Characteristicsstorage elastic modulus G′ of 40° C., 0.06 rad/s 2.2 × 10³ 6.5 × 10³ 1.4× 10⁴ 3.2 × 10⁴ of prepreg surface resin (Pa) 40° C., 6.28 rad/s 5.4 ×10⁴ 9.1 × 10⁵ 9.4 × 10⁴ 5.3 × 10⁵ 40° C., 314 rad/s 1.3 × 10⁶ 2.1 × 10⁶5.8 × 10⁶ 2.3 × 10⁷ storage elastic modulus G′ of 40° C., 0.06 rad/ssame on same on same on same on opposite-side surface resin (Pa) 40° C.,6.28 rad/s both sides both sides both sides both sides 40° C., 314 rad/sglass transition temperature of prepreg (° C.) 5.3 9.5 14.4 19.7 degreeof conversion of epoxy resin composition (%) 1.5 3.4 5.6 8.1 tackinessbetween prepreg and tackiness value (N) 0.2 0.0 0.0 0.0 metal (25° C.)acceptable A B C D E rejectable B A A A drapability (25° C.) deflectionangle 31 25 20 15 acceptable A B C D E rejectable A B C D overallevaluation acceptable A B C D E rejectable B A B C Characteristics glasstransition temperature of cured product (° C.) 205 205 205 205 of curedproduct phase-separated structure existing existing existing existingtensile strength (MPa) — — — — Example Example Example Example 22 23 2425 Characteristics storage elastic modulus G′ of 40° C., 0.06 rad/s 2.5× 10⁵ 5.5 × 10³ 9.4 × 10³ 4.2 × 10⁴ of prepreg surface resin (Pa) 40°C., 6.28 rad/s 1.4 × 10⁶ 8.1 × 10⁵ 8.4 × 10⁴ 6.3 × 10⁵ 40° C., 314 rad/s1.8 × 10⁸ 1.1 × 10⁶ 4.8 × 10⁶ 3.3 × 10⁷ storage elastic modulus G′ of40° C., 0.06 rad/s same on same on same on same on opposite-side surfaceresin (Pa) 40° C., 6.28 rad/s both sides both sides both sides bothsides 40° C., 314 rad/s glass transition temperature of prepreg (° C.)24.8 10.4 16.1 21.3 degree of conversion of epoxy resin composition (%)10.4 3.7 5.8 8.7 tackiness between prepreg and tackiness value (N) 0.00.0 0.0 0.0 metal (25° C.) acceptable A B C D E rejectable A A A Adrapability (25° C.) deflection angle 11 23 19 12 acceptable A B C D Erejectable D B C D overall evaluation acceptable A B C D E rejectable CA B C Characteristics glass transition temperature of cured product (°C.) 205 185 185 185 of cured product phase-separated structure existingexisting existing existing tensile strength (MPa) — — — —

TABLE 17 Example Example Example Example 26 27 28 29 Characteristicsstorage elastic modulus G′ of 40° C., 0.06 rad/s 2.2 × 10³ 6.5 × 10³ 6.5× 10³ 1.4 × 10³ of prepreg surface resin (Pa) 40° C., 6.28 rad/s 5.4 ×10⁴ 9.1 × 10⁵ 9.1 × 10⁵ 1.1 × 10⁵ 40° C., 314 rad/s 1.3 × 10⁶ 2.1 × 10⁶2.1 × 10⁶ 1.5 × 10⁶ storage elastic modulus G′ of 40° C., 0.06 rad/s 2.0× 10¹ 2.0 × 10¹ 2.2 × 10³ same on opposite-side surface resin (Pa) 40°C., 6.28 rad/s 1.2 × 10³ 1.2 × 10³ 5.4 × 10⁴ both sides 40° C., 314rad/s 3.3 × 10⁴ 3.3 × 10⁴ 1.3 × 10⁶ glass transition temperature ofprepreg (° C.) 3.9 6.4 8.5 5.3 degree of conversion of epoxy resincomposition (%) 0.8 1.6 2.5 2.3 tackiness between prepreg and tackinessvalue (N) 0.2 0.0 0.0 0.3 metal (25° C.) acceptable A B C D E rejectableB A A C drapability (25° C.) deflection angle 35 31 26 30 acceptable A BC D E rejectable A A B B overall evaluation acceptable A B C D Erejectable A A A C Characteristics glass transition temperature of curedproduct (° C.) 205 205 205 182 of cured product phase-separatedstructure existing existing existing absent tensile strength (MPa) — — —2,920 Example Example Example Example 30 31 32 33 Characteristicsstorage elastic modulus G′ of 40° C., 0.06 rad/s 4.7 × 10³ 1.1 × 10⁴ 1.4× 10³ 4.7 × 10³ of prepreg surface resin (Pa) 40° C., 6.28 rad/s 2.7 ×10⁵ 9.0 × 10⁵ 1.1 × 10⁵ 2.7 × 10⁵ 40° C., 314 rad/s 3.8 × 10⁶ 5.0 × 10⁷1.5 × 10⁶ 3.8 × 10⁶ storage elastic modulus G′ of 40° C., 0.06 rad/ssame on same on 4.5 × 10² 4.5 × 10² opposite-side surface resin (Pa) 40°C., 6.28 rad/s both sides both sides 4.5 × 10⁴ 4.5 × 10⁴ 40° C., 314rad/s 5.0 × 10⁵ 5.0 × 10⁵ glass transition temperature of prepreg (° C.)10.3 19.7 3.5 5.8 degree of conversion of epoxy resin composition (%)7.0 14.1 1.3 3.7 tackiness between prepreg and tackiness value (N) 0.00.0 0.3 0.0 metal (25° C.) acceptable A B C D E rejectable A A C Adrapability (25° C.) deflection angle 25 14 34 30 acceptable A B C D Erejectable B D A B overall evaluation acceptable A B C D E rejectable AC B A Characteristics glass transition temperature of cured product (°C.) 182 182 182 182 of cured product phase-separated structure absentabsent absent absent tensile strength (MPa) 2,910 2,930 2,920 2,910

TABLE 18 Example Example Example Example 34 35 36 37 Characteristicsstorage elastic modulus G′ of 40° C., 0.06 rad/s 4.7 × 10³ 2.8 × 10³ 3.8× 10³ 1.4 × 10⁴ of prepreg surface resin (Pa) 40° C., 6.28 rad/s 2.7 ×10⁵ 1.6 × 10⁵ 2.2 × 10⁵ 8.1 × 10⁵ 40° C., 314 rad/s 3.8 × 10⁶ 2.3 × 10⁶3.0 × 10⁶ 1.1 × 10⁷ storage elastic modulus G′ of 40° C., 0.06 rad/s 1.4× 10³ same on same on same on opposite-side surface resin (Pa) 40° C.,6.28 rad/s 1.1 × 10⁵ both sides both sides both sides 40° C., 314 rad/s1.5 × 10⁶ glass transition temperature of prepreg (° C.) 7.7 8.9 9.711.6 degree of conversion of epoxy resin composition (%) 4.4 7.3 7.4 7.1tackiness between prepreg and tackiness value (N) 0.0 0.2 0.1 0.0 metal(25° C.) acceptable A B C D E rejectable A B B A drapability (25° C.)deflection angle 25 25 25 24 acceptable A B C D E rejectable B B B Coverall evaluation acceptable A B C D E rejectable A B B BCharacteristics glass transition temperature of cured product (° C.) 182198 191 182 of cured product phase-separated structure absent absentabsent absent tensile strength (MPa) 2,920 2,780 2,840 3,080 ExampleExample Example Example 38 39 40 41 Characteristics storage elasticmodulus G′ of 40° C., 0.06 rad/s 3.7 × 10⁴ 3.3 × 10³ 1.1 × 10⁴ 9.8 × 10³of prepreg surface resin (Pa) 40° C., 6.28 rad/s 2.4 × 10⁶ 1.6 × 10⁵ 7.6× 10⁵ 7.2 × 10⁵ 40° C., 314 rad/s 3.1 × 10⁷ 2.1 × 10⁶ 9.8 × 10⁶ 9.5 ×10⁶ storage elastic modulus G′ of 40° C., 0.06 rad/s same on same onsame on same on opposite-side surface resin (Pa) 40° C., 6.28 rad/s bothsides both sides both sides both sides 40° C., 314 rad/s glasstransition temperature of prepreg (° C.) 12.2 9.3 11.1 10.8 degree ofconversion of epoxy resin composition (%) 7.0 7.3 7.2 7.0 tackinessbetween prepreg and tackiness value (N) 0.0 0.2 0.0 0.0 metal (25° C.)acceptable A B C D E rejectable A B A A drapability (25° C.) deflectionangle 22 31 24 25 acceptable A B C D E rejectable C B C B overallevaluation acceptable A B C D E rejectable B B B A Characteristics glasstransition temperature of cured product (° C.) 183 175 181 188 of curedproduct phase-separated structure absent absent absent absent tensilestrength (MPa) 3,220 2,990 2,900 2,790

TABLE 19 Example Example Example Example 42 43 44 45 Characteristicsstorage elastic modulus G′ of 40° C., 0.06 rad/s 1.0 × 10³ 3.6 × 10³ 8.4× 10³ 1.0 × 10³ of prepreg surface resin (Pa) 40° C., 6.28 rad/s 7.2 ×10⁴ 1.7 × 10⁵ 5.7 × 10⁵ 7.2 × 10⁴ 40° C., 314 rad/s 7.0 × 10⁵ 1.6 × 10⁶2.3 × 10⁷ 7.0 × 10⁵ storage elastic modulus G′ of 40° C., 0.06 rad/ssame on same on same on 3.5 × 10² opposite-side surface resin (Pa) 40°C., 6.28 rad/s both sides both sides both sides 3.0 × 10⁴ 40° C., 314rad/s 2.4 × 10⁵ glass transition temperature of prepreg (° C.) 4.2 9.218.9 3.2 degree of conversion of epoxy resin composition (%) 2.0 6.813.7 1.1 tackiness between prepreg and tackiness value (N) 0.3 0.0 0.00.3 metal (25° C.) acceptable A B C D E rejectable C A A C drapability(25° C.) deflection angle 31 27 16 36 acceptable A B C D E rejectable AB D A overall evaluation acceptable A B C D E rejectable B A C BCharacteristics glass transition temperature of cured product (° C.) 190190 190 190 of cured product phase-separated structure absent absentabsent absent tensile strength (MPa) 2,800 2,820 2,810 2,810 ExampleExample Example Example 46 47 48 49 Characteristics storage elasticmodulus G′ of 40° C., 0.06 rad/s 3.6 × 10³ 3.6 × 10³ 4.8 × 10³ 4.1 × 10³of prepreg surface resin (Pa) 40° C., 6.28 rad/s 1.7 × 10⁵ 1.7 × 10⁵ 2.6× 10⁵ 2.2 × 10⁵ 40° C., 314 rad/s 1.6 × 10⁶ 1.6 × 10⁶ 2.3 × 10⁶ 2.0 ×10⁶ storage elastic modulus G′ of 40° C., 0.06 rad/s 3.5 × 10² 1.0 × 10³same on same on opposite-side surface resin (Pa) 40° C., 6.28 rad/s 3.0× 10⁴ 7.2 × 10⁴ both sides both sides 40° C., 314 rad/s 2.4 × 10⁵ 7.0 ×10⁵ glass transition temperature of prepreg (° C.) 5.5 7.5 9.9 9.3degree of conversion of epoxy resin composition (%) 3.3 4.3 7.3 7.4tackiness between prepreg and tackiness value (N) 0.0 0.0 0.0 0.0 metal(25° C.) acceptable A B C D E rejectable A A A A drapability (25° C.)deflection angle 32 27 27 27 acceptable A B C D E rejectable B B B Boverall evaluation acceptable A B C D E rejectable A A A ACharacteristics glass transition temperature of cured product (° C.) 190190 204 196 of cured product phase-separated structure absent absentabsent absent tensile strength (MPa) 2,820 2,820 2,670 2,750

TABLE 20 Example Example Example Example 50 51 52 53 Characteristicsstorage elastic modulus G′ of 40° C., 0.06 rad/s 1.1 × 10⁴ 2.2 × 10⁴ 2.6× 10³ 9.8 × 10³ of prepreg surface resin (Pa) 40° C., 6.28 rad/s 5.2 ×10⁵ 1.0 × 10⁶ 1.1 × 10⁵ 4.8 × 10⁵ 40° C., 314 rad/s 5.1 × 10⁶ 1.2 × 10⁷9.0 × 10⁵ 4.2 × 10⁶ storage elastic modulus G′ of 40° C., 0.06 rad/ssame on same on same on same on opposite-side surface resin (Pa) 40° C.,6.28 rad/s both sides both sides both sides both sides 40° C., 314 rad/sglass transition temperature of prepreg (° C.) 10.0 11.0 3.9 10.3 degreeof conversion of epoxy resin composition (%) 7.4 7.5 7.7 7.6 tackinessbetween prepreg and tackiness value (N) 0.0 0.0 0.2 0.0 metal (25° C.)acceptable A B C D E rejectable A A B A drapability (25° C.) deflectionangle 27 24 33 24 acceptable A B C D E rejectable B C A C overallevaluation acceptable A B C D E rejectable A B B B Characteristics glasstransition temperature of cured product (° C.) 190 190 178 188 of curedproduct phase-separated structure absent absent absent absent tensilestrength (MPa) 2,930 3,050 2,870 2,780 Example Example Example Example54 55 56 57 Characteristics storage elastic modulus G′ of 40° C., 0.06rad/s 1.2 × 10⁴ 1.2 × 10³ 4.7 × 10³ 9.2 × 10³ of prepreg surface resin(Pa) 40° C., 6.28 rad/s 5.3 × 10⁵ 7.2 × 10⁴ 1.9 × 10⁵ 6.3 × 10⁵ 40° C.,314 rad/s 4.7 × 10⁶ 7.0 × 10⁵ 2.0 × 10⁶ 2.6 × 10⁷ storage elasticmodulus G′ of 40° C., 0.06 rad/s same on same on same on same onopposite-side surface resin (Pa) 40° C., 6.28 rad/s both sides bothsides both sides both sides 40° C., 314 rad/s glass transitiontemperature of prepreg (° C.) 10.9 4.4 9.4 19.1 degree of conversion ofepoxy resin composition (%) 7.8 2.2 6.9 13.9 tackiness between prepregand tackiness value (N) 0.0 0.3 0.0 0.0 metal (25° C.) acceptable A B CD E rejectable A C A A drapability (25° C.) deflection angle 22 30 26 15acceptable A B C D E rejectable C B B D overall evaluation acceptable AB C D E rejectable B C A C Characteristics glass transition temperatureof cured product (° C.) 198 192 192 192 of cured product phase-separatedstructure absent absent absent absent tensile strength (MPa) 2,700 2,8402,830 2,830

TABLE 21 Example Example Example Example 58 59 60 61 Characteristicsstorage elastic modulus G′ of 40° C., 0.06 rad/s 1.2 × 10³ 4.7 × 10³ 4.7× 10³ 5.3 × 10³ of prepreg surface resin (Pa) 40° C., 6.28 rad/s 7.2 ×10⁴ 1.9 × 10⁵ 1.9 × 10⁵ 2.4 × 10⁵ 40° C., 314 rad/s 7.0 × 10⁵ 2.0 × 10⁶2.0 × 10⁶ 2.5 × 10⁶ storage elastic modulus G′ of 40° C., 0.06 rad/s 2.3× 10² 2.3 × 10² 1.2 × 10³ same on opposite-side surface resin (Pa) 40°C., 6.28 rad/s 2.8 × 10⁴ 2.8 × 10⁴ 7.2 × 10⁴ both sides 40° C., 314rad/s 3.2 × 10⁵ 3.2 × 10⁵ 7.0 × 10⁵ glass transition temperature ofprepreg (° C.) 3.3 5.6 7.6 10.1 degree of conversion of epoxy resincomposition (%) 1.3 3.6 4.8 8.3 tackiness between prepreg and tackinessvalue (N) 0.3 0.0 0.0 0.0 metal (25° C.) acceptable A B C D E rejectableC A A A drapability (25° C.) deflection angle 35 31 26 26 acceptable A BC D E rejectable A B B B overall evaluation acceptable A B C D Erejectable B A A A Characteristics glass transition temperature of curedproduct (° C.) 192 192 192 206 of cured product phase-separatedstructure absent absent absent absent tensile strength (MPa) 2,840 2,8202,830 2,690 Example Example Example Example 62 63 64 65 Characteristicsstorage elastic modulus G′ of 40° C., 0.06 rad/s 5.0 × 10³ 1.4 × 10⁴ 2.6× 10⁴ 3.1 × 10³ of prepreg surface resin (Pa) 40° C., 6.28 rad/s 2.1 ×10⁵ 6.2 × 10⁵ 1.2 × 10⁶ 1.4 × 10⁵ 40° C., 314 rad/s 2.3 × 10⁶ 5.9 × 10⁶1.4 × 10⁷ 1.1 × 10⁶ storage elastic modulus G′ of 40° C., 0.06 rad/ssame on same on same on same on opposite-side surface resin (Pa) 40° C.,6.28 rad/s both sides both sides both sides both sides 40° C., 314 rad/sglass transition temperature of prepreg (° C.) 9.6 10.2 11.3 4.2 degreeof conversion of epoxy resin composition (%) 8.4 8.4 8.5 8.6 tackinessbetween prepreg and tackiness value (N) 0.0 0.0 0.0 0.2 metal (25° C.)acceptable A B C D E rejectable A A A B drapability (25° C.) deflectionangle 26 25 23 32 acceptable A B C D E rejectable B B C A overallevaluation acceptable A B C D E rejectable A A B B Characteristics glasstransition temperature of cured product (° C.) 199 192 193 181 of curedproduct phase-separated structure absent absent absent absent tensilestrength (MPa) 2,780 2,960 3,110 2,930

TABLE 22 Example Example Example Example 66 67 68 69 Characteristicsstorage elastic modulus G′ of 40° C., 0.06 rad/s 1.2 × 10⁴ 1.0 × 10⁴ 1.5× 10⁴ 9.4 × 10³ of prepreg surface resin (Pa) 40° C., 6.28 rad/s 6.2 ×10⁵ 5.8 × 10⁵ 8.1 × 10⁵ 6.8 × 10⁵ 40° C., 314 rad/s 5.5 × 10⁶ 5.3 × 10⁶1.1 × 10⁷ 9.1 × 10⁶ storage elastic modulus G′ of 40° C., 0.06 rad/ssame on same on same on same on opposite-side surface resin (Pa) 40° C.,6.28 rad/s both sides both sides both sides both sides 40° C., 314 rad/sglass transition temperature of prepreg (° C.) 10.5 10.1 12.6 11.5degree of conversion of epoxy resin composition (%) 8.6 8.1 4.3 4.0tackiness between prepreg and tackiness value (N) 0.0 0.0 0.0 0.0 metal(25° C.) acceptable A B C D E rejectable A A A A drapability (25° C.)deflection angle 24 25 22 25 acceptable A B C D E rejectable C B C Boverall evaluation acceptable A B C D E rejectable B A B ACharacteristics glass transition temperature of cured product (° C.) 191183 204 202 of cured product phase-separated structure absent absentabsent absent tensile strength (MPa) 2,900 2,960 — — Example ExampleExample Example 70 71 72 73 Characteristics storage elastic modulus G′of 40° C., 0.06 rad/s 1.9 × 10⁴ 1.3 × 10⁴ 1.7 × 10⁴ 9.0 × 10³ of prepregsurface resin (Pa) 40° C., 6.28 rad/s 8.5 × 10⁵ 7.9 × 10⁵ 8.0 × 10⁵ 6.0× 10⁵ 40° C., 314 rad/s 1.5 × 10⁷ 9.5 × 10⁶ 9.4 × 10⁶ 8.3 × 10⁶ storageelastic modulus G′ of 40° C., 0.06 rad/s same on same on same on same onopposite-side surface resin (Pa) 40° C., 6.28 rad/s both sides bothsides both sides both sides 40° C., 314 rad/s glass transitiontemperature of prepreg (° C.) 13.1 12.3 12.4 11.0 degree of conversionof epoxy resin composition (%) 4.8 4.2 5.3 5.1 tackiness between prepregand tackiness value (N) 0.0 0.0 0.0 0.0 metal (25° C.) acceptable A B CD E rejectable A A A A drapability (25° C.) deflection angle 20 22 21 23acceptable A B C D E rejectable C C C C overall evaluation acceptable AB C D E rejectable B B B B Characteristics glass transition temperatureof cured product (° C.) 206 203 203 201 of cured product phase-separatedstructure absent absent absent absent tensile strength (MPa) — — — —

TABLE 23 Comparative Comparative Comparative Comparative example 1example 2 example 3 example 4 Characteristics storage elastic modulus G′of 40° C., 0.06 rad/s 2.0 × 10¹ 9.1 × 10⁵ 2.2 × 10¹ 1.0 × 10⁶ of prepregsurface resin (Pa) 40° C., 6.28 rad/s 1.2 × 10³ 2.5 × 10⁷ 1.3 × 10³ 3.1× 10⁷ 40° C., 314 rad/s 3.5 × 10⁴ >10⁹  3.6 × 10⁴ >10⁹  storage elasticmodulus G′ of 40° C., 0.06 rad/s same on same on same on same onopposite-side surface resin (Pa) 40° C., 6.28 rad/s both sides bothsides both sides both sides 40° C., 314 rad/s glass transitiontemperature of prepreg (° C.) −7.5 40.5 0.0 39.4 degree of conversion ofepoxy resin composition (%) 0.0 30.2 0.0 28.3 tackiness between prepregand tackiness value (N) 1.5  0.0 1.2  0.0 metal (25° C.) acceptable A BC D E rejectable E A E A drapability (25° C.) deflection angle 40 5 38 4acceptable A B C D E rejectable A E A E overall evaluation acceptable AB C D E rejectable E E E E Characteristics glass transition temperatureof cured product (° C.) 200 200   205 205   of cured productphase-separated structure absent absent absent absent tensile strength(MPa) — — — — Comparative Comparative Comparative Comparative example 5example 6 example 7 example 8 Characteristics storage elastic modulus G′of 40° C., 0.06 rad/s 2.1 × 10¹ 8.8 × 10⁵ 6.4 × 10³ 9.5 × 10² of prepregsurface resin (Pa) 40° C., 6.28 rad/s 1.2 × 10³ 2.4 × 10⁷ 8.8 × 10⁴ 1.1× 10⁴ 40° C., 314 rad/s 3.3 × 10⁴ >10⁹  1.7 × 10⁶ 5.9 × 10⁵ storageelastic modulus G′ of 40° C., 0.06 rad/s same on same on same on same onopposite-side surface resin (Pa) 40° C., 6.28 rad/s both sides bothsides both sides both sides 40° C., 314 rad/s glass transitiontemperature of prepreg (° C.) −8.2 38.1 6.4 1.1 degree of conversion ofepoxy resin composition (%) 0.0 31.4 0.0 0.0 tackiness between prepregand tackiness value (N) 1.4  0.0 0.3 1.1 metal (25° C.) acceptable A B CD E rejectable E A C E drapability (25° C.) deflection angle 42 5  26 35acceptable A B C D E rejectable A E B A overall evaluation acceptable AB C D E rejectable E E C E Characteristics glass transition temperatureof cured product (° C.) 190 190   170 190 of cured productphase-separated structure absent absent absent absent tensile strength(MPa) — — — —

TABLE 24 Comparative Comparative Comparative Comparative Comparativeexample 9 example 10 example 11 example 12 example 13 Characteristicsstorage elastic modulus G′ of 40° C., 0.06 rad/s 2.0 × 10¹ 8.6 × 10⁵ 6.6× 10³ 9.8 × 10² 4.5 × 10² of prepreg surface resin (Pa) 40° C., 6.28rad/s 1.1 × 10³ 2.1 × 10⁷ 8.9 × 10⁴ 1.4 × 10⁴ 4.5 × 10⁴ 40° C., 314rad/s 3.3 × 10⁴ >10⁹  2.0 × 10⁶ 6.3 × 10⁵ 5.0 × 10⁵ storage elasticmodulus G′ of 40° C., 0.06 rad/s same on same on same on same on same onopposite-side surface resin (Pa) 40° C., 6.28 rad/s both sides bothsides both sides both sides both sides 40° C., 314 rad/s glasstransition temperature of prepreg (° C.) 1.8 40.5 6.4 1.1 −1.5 degree ofconversion of epoxy resin 0.0 30.2 0.0 0.0 0.0 composition (%) tackinessbetween prepreg and tackiness value (N) 1.0  0.0 0.3 1.1 2.0 metal (25°C.) acceptable A B C E A C E E D E rejectable drapability (25° C.)deflection angle 40 6  26 35 42 acceptable A B C A E B A A D Erejectable overall evaluation acceptable A B C E E C E E D E rejectableCharacteristics glass transition temperature of cured product (° C.) 205205   170 185 182 of cured product phase-separated structure existingexisting existing existing absent tensile strength (MPa) — — — — 2,930Comparative Comparative Comparative Comparative example 14 example 15example 16 example 17 Characteristics storage elastic modulus G′ of 40°C., 0.06 rad/s 1.2 × 10⁶ 3.5 × 10² 8.3 × 10⁵ 2.3 × 10² of prepregsurface resin (Pa) 40° C., 6.28 rad/s 8.8 × 10⁸ 3.0 × 10⁴ 5.5 × 10⁸ 2.8× 10⁴ 40° C., 314 rad/s >10⁹  2.4 × 10⁵ >10⁹  3.2 × 10⁵ storage elasticmodulus G′ of 40° C., 0.06 rad/s same on same on same on same onopposite-side surface resin (Pa) 40° C., 6.28 rad/s both sides bothsides both sides both sides 40° C., 314 rad/s glass transitiontemperature of prepreg (° C.) 41.2 −1.2 39.5 −1.0 degree of conversionof epoxy resin 28.6 0.0 27.4 0.0 composition (%) tackiness betweenprepreg and tackiness value (N)  0.0 2.2  0.0 2.5 metal (25° C.)acceptable A B C A E A E D E rejectable drapability (25° C.) deflectionangle 5  44 6  45 acceptable A B C E A E A D E rejectable overallevaluation acceptable A B C E E E E D E rejectable Characteristics glasstransition temperature of cured product (° C.) 182   190 190   192 ofcured product phase-separated structure absent absent absent absenttensile strength (MPa) 2,920   2,810 2,820   2,840

TABLE 25 Comparative Comparative Comparative Comparative Comparativeexample 18 example 19 example 20 example 21 example 22 Characteristicsstorage elastic modulus G′ of 40° C., 0.06 rad/s 9.1 × 10⁵ 4.3 × 10³ 1.3× 10³ 1.6 × 10³ 8.8 × 10² of prepreg surface resin (Pa) 40° C., 6.28rad/s 6.1 × 10⁸ 5.1 × 10⁵ 2.1 × 10⁵ 2.4 × 10⁵ 8.9 × 10⁴ 40° C., 314rad/s >10⁹  8.0 × 10⁶ 4.9 × 10⁶ 5.3 × 10⁶ 9.8 × 10⁵ storage elasticmodulus G′ of 40° C., 0.06 rad/s same on same on same on same on same onopposite-side surface resin (Pa) 40° C., 6.28 rad/s both sides bothsides both sides both sides both sides 40° C., 314 rad/s glasstransition temperature of prepreg (° C.) 40.6 10.3 9.2 9.6 5.6 degree ofconversion of epoxy resin 28.1 0.0 0.0 0.0 0.0 composition (%) tackinessbetween prepreg and tackiness value (N)  0.0 0.2 0.4 0.3 1.4 metal (25°C.) acceptable A B C A B C C E D E rejectable drapability (25° C.)deflection angle 7 25 27 26 36 acceptable A B C E B B B A D E rejectableoverall evaluation acceptable A B C E B C C E D E rejectableCharacteristics glass transition temperature of cured product (° C.)192   163 169 171 204 of cured product phase-separated structure absentabsent absent absent absent tensile strength (MPa) 2,840   2,920 2,8402,750 — Comparative Comparative Comparative Comparative example 23example 24 example 25 example 26 Characteristics storage elastic modulusG′ of 40° C., 0.06 rad/s 1.6 × 10⁶ 9.7 × 10² 1.9 × 10⁶ 9.2 × 10² ofprepreg surface resin (Pa) 40° C., 6.28 rad/s 9.2 × 10⁸ 1.2 × 10⁵ 9.7 ×10⁸ 9.7 × 10⁴ 40° C., 314 rad/s >10⁹  1.5 × 10⁷ >10⁹  1.1 × 10⁷ storageelastic modulus G′ of 40° C., 0.06 rad/s same on same on same on same onopposite-side surface resin (Pa) 40° C., 6.28 rad/s both sides bothsides both sides both sides 40° C., 314 rad/s glass transitiontemperature of prepreg (° C.) 43.1 8.2 44.7 7.4 degree of conversion ofepoxy resin 30.1 0.0 31.8 0.0 composition (%) tackiness between prepregand tackiness value (N)  0.0 1.0  0.0 1.1 metal (25° C.) acceptable A BC A E A E D E rejectable drapability (25° C.) deflection angle 4  33 3 38 acceptable A B C E A E A D E rejectable overall evaluation acceptableA B C E D E D D E rejectable Characteristics glass transitiontemperature of cured product (° C.) 204   206 206   203 of cured productphase-separated structure absent absent absent absent tensile strength(MPa) — — — —

TABLE 26 Comparative Comparative Comparative Comparative example 27example 28 example 29 example 30 Characteristics storage elastic modulusG′ of 40° C., 0.06 rad/s 1.8 × 10⁶ 3.1 × 10⁴ 1.8 × 10³ 3.4 × 10⁵ ofprepreg surface resin (Pa) 40° C., 6.28 rad/s 9.3 × 10⁸ 4.8 × 10⁵ 4.6 ×10⁴ 5.2 × 10⁶ 40° C., 314 rad/s >10⁹  2.0 × 10⁷ 1.0 × 10⁶ 2.5 × 10⁸storage elastic modulus G′ of 40° C., 0.06 rad/s same on same on same onsame on opposite-side surface resin (Pa) 40° C., 6.28 rad/s both sidesboth sides both sides both sides 40° C., 314 rad/s glass transitiontemperature of prepreg (° C.) 42.9 10.0 8.9 11.4 degree of conversion ofepoxy resin composition (%) 30.8 0.0 0.0 0.0 tackiness between prepregand tackiness value (N)  0.0 0.5 0.7 0.3 metal (25° C.) acceptable A B CD E rejectable A D D C drapability (25° C.) deflection angle 5 30 32 28acceptable A B C D E rejectable E B A B overall evaluation acceptable AB C D E rejectable E D C C Characteristics glass transition temperatureof cured product (° C.) 202   195 195 195 of cured productphase-separated structure absent absent absent absent tensile strength(MPa) — 2,280 2,200 2,340 Comparative Comparative ComparativeComparative example 31 example 32 example 33 example 34 Characteristicsstorage elastic modulus G′ of 40° C., 0.06 rad/s 1.5 × 10⁵ 1.5 × 10³ 1.2× 10³ 2.6 × 10³ of prepreg surface resin (Pa) 40° C., 6.28 rad/s 2.3 ×10⁶ 3.8 × 10⁴ 3.6 × 10⁴ 4.8 × 10⁴ 40° C., 314 rad/s 1.1 × 10⁸ 9.2 × 10⁵8.5 × 10⁵ 1.6 × 10⁶ storage elastic modulus G′ of 40° C., 0.06 rad/ssame on same on same on same on opposite-side surface resin (Pa) 40° C.,6.28 rad/s both sides both sides both sides both sides 40° C., 314 rad/sglass transition temperature of prepreg (° C.) 13.8 8.4 5.8 10.6 degreeof conversion of epoxy resin composition (%) 0.0 0.0 25.2 28.7 tackinessbetween prepreg and tackiness value (N) 0.2 1.0 0.3 0.1 metal (25° C.)acceptable A B C D E rejectable B E C B drapability (25° C.) deflectionangle 25 34 24 18 acceptable A B C D E rejectable B A C D overallevaluation acceptable A B C D E rejectable B E D D Characteristics glasstransition temperature of cured product (° C.) 180 210 190 190 of curedproduct phase-separated structure absent absent absent absent tensilestrength (MPa) 2,400 2,260 2,450 2,440

Example 1

An epoxy resin composition 1 was prepared by mixing 50 parts of jER® 630and 50 parts of jER® 807 as the component [B], 35 parts of Seikacure-Sas the component [C], and 35 parts of Virantage® VW-10700RP as thecomponent [D] according to the epoxy resin composition preparationprocedure described in (1). Then, 25 parts of Orgasol® 1002D Nat 1adopted as the component [E] was added to the epoxy resin composition 1to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for60 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 14, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 2.1×10³ to 1.2×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had good dry property asevaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9) and there was no surface resin remainingon the metal plate after removal by pulling. It also had gooddrapability as evaluated by the prepreg drapability evaluation proceduredescribed in (10). The prepreg had a glass transition temperature of5.2° C. as measured by the prepreg's glass transition temperaturemeasurement procedure described in (4) and the epoxy resin compositionin the prepreg had a degree of conversion of 5.7% as measured by theepoxy resin composition's degree of conversion measurement proceduredescribed in (7). Furthermore, the mass ratio among the constituents ofthe component [B] in the prepreg that included a preliminary reactionproduct as calculated by the procedure described in (7) showed no changefrom the mass ratio based on the contents of the constituents of thecomponent [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of200° C. as measured according to the procedure described in (13).

Examples 2 to 5

Except for changing the heat-treatment time of the prepreg precursor asspecified in Table 1, the same procedure as in Example 1 was carried outto prepare a prepreg.

As shown in Table 14, the prepreg prepared in Example 2, which containeda surface resin having a G′ value in the range of 6.7×10³ to 2.0×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s, had a particularly good dry property asevaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9), with no surface resin remaining on themetal plate after removal by pulling, and also had good drapability asevaluated by the prepreg drapability evaluation procedure described in(10). Furthermore, the prepreg prepared in Example 3, which contained asurface resin having a G′ value in the range of 1.3×10⁴ to 5.6×10⁶ Pa asmeasured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s, had particularly good dry property asevaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9) and there was no surface resin remainingon the metal plate after removal by pulling. The drapability asevaluated by the prepreg drapability evaluation procedure described in(10) was at an acceptable level although slightly lower than in Example2. The prepregs prepared in Examples 4 and 5, each containing a surfaceresin having a G′ value in the range of 1.0×10³ to 2.0×10⁸ Pa asmeasured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s, had particularly good dry property and alsohad a permissible level of drapability although a little worse comparedwith Examples 1 to 3. Other measurement results are shown in Table 14.Furthermore, the mass ratio among the constituents of the component [B]in the prepreg that included a preliminary reaction product ascalculated by the procedure described in (7) showed no change from themass ratio based on the contents of the constituents of the component[B] before the preliminary reaction.

Example 6

An epoxy resin composition 1 was prepared by mixing 50 parts of jER® 630and 50 parts of jER® 807 as the component [B], 35 parts of Seikacure-Sas the component [C], and 35 parts of Virantage® VW-10700RP as thecomponent [D] according to the epoxy resin composition preparationprocedure described in (1). Then, 25 parts of Orgasol® 1002D Nat 1adopted as the component [E] was added to the epoxy resin composition 1to prepare an epoxy resin composition 2.

Using the epoxy resin composition 2 prepared above, a resin film 2 wasprepared according to the prepreg precursor preparation proceduredescribed in (3). The resin film 2 prepared above was heat-treated for60 hours in a similar way to the prepreg precursor heat-treatmentprocedure described in (5) to provide a resin film 2′ that included apreliminary reaction product of [B] and [C].

Furthermore, when a prepreg is prepared using Torayca® T800S-24K-10E asthe component [A] according to the prepreg precursor preparationprocedure described in (3), an impregnated first prepreg was sandwichedbetween the resin films 2 and 2′ to provide a prepreg having the resinfilm 2 as one surface resin and the resin film 2′ as the other surfaceresin.

As shown in Table 14, the surface resin in the prepreg prepared abovethat was higher in G′ had a G′ value in the range of 2.1×10³ to 1.2×10⁶Pa as measured at a temperature of 40° C. and an angular frequency inthe range of 0.06 to 314 rad/s. The prepreg had good dry property asevaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9) and there was no surface resin remainingon the metal plate after removal by pulling. It had particularly gooddrapability as evaluated by the prepreg drapability evaluation proceduredescribed in (10). The prepreg had a glass transition temperature of−1.4° C. as measured by the prepreg's glass transition temperaturemeasurement procedure described in (4) and the epoxy resin compositionin the prepreg had a degree of conversion of 3.5% as measured by theepoxy resin composition's degree of conversion measurement proceduredescribed in (7).

Furthermore, the mass ratio among the constituents of the component [B]in the prepreg that included a preliminary reaction product ascalculated by the procedure described in (7) showed no change from themass ratio based on the contents of the constituents of the component[B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of200° C. as measured according to the procedure described in (13).

Here, a polypropylene cover film with a thickness of 50 μm was stuck onthe surface of the prepreg's surface resin that was the lower in G′ andresults showed good sticking property.

Example 7

Except that the resin film 2 was heat-treated for 90 hours instead of 60hours when producing the resin film 2′, the same procedure as in Example6 was carried out to prepare a prepreg.

As shown in Table 14, the surface resin in the prepreg prepared abovethat was higher in G′ had a G′ value in the range of 6.7×10³ to 2.0×10⁶Pa as measured at a temperature of 40° C. and an angular frequency inthe range of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling. It also hadgood drapability as evaluated by the prepreg drapability evaluationprocedure described in (10). The prepreg had a glass transitiontemperature of 1.5° C. as measured by the prepreg's glass transitiontemperature measurement procedure described in (4) and the epoxy resincomposition in the prepreg had a degree of conversion of 4.9% asmeasured by the epoxy resin composition's degree of conversionmeasurement procedure described in (7). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of200° C. as measured according to the procedure described in (13).

Here, a polypropylene cover film with a thickness of 50 μm was stuck onthe surface of the prepreg's surface resin that was the lower in G′ andresults showed good sticking property.

Example 8

Except that the resin film 2 was heat-treated for 60 hours or 90 hoursto prepare two resin films 2′ and 2″ that differed in the content of thepreliminary reaction product and that they were used to sandwich animpregnated first prepreg, the same procedure as in Example 6 wascarried out to prepare a prepreg.

As shown in Table 14, the surface resin in the prepreg prepared abovethat was higher in G′ had a G′ value in the range of 6.7×10³ to 2.0×10⁶Pa as measured at a temperature of 40° C. and an angular frequency inthe range of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling. It also hadgood drapability as evaluated by the prepreg drapability evaluationprocedure described in (10). The prepreg had a glass transitiontemperature of 7.5° C. as measured by the prepreg's glass transitiontemperature measurement procedure described in (4) and the epoxy resincomposition in the prepreg had a degree of conversion of 6.9% asmeasured by the epoxy resin composition's degree of conversionmeasurement procedure described in (7). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of200° C. as measured according to the procedure described in (13).

Here, a polypropylene cover film with a thickness of 50 μm was stuck onthe surface of the prepreg's surface resin that was the lower in G′ andresults showed a slight deterioration in sticking property though it isstill at an acceptable level.

Example 9

An epoxy resin composition 1 was prepared by mixing 10 parts of jER®630, 60 parts of Sumiepoxy® ELM434, and 30 parts of jER® 807 as thecomponent [B], 35 parts of Seikacure-S as the component [C], and 20parts of Sumikaexcel® PES5003P as the component [D] according to theepoxy resin composition preparation procedure described in (1). Then, 20parts of Orgasol® 1002D Nat 1 adopted as the component [E] was added tothe epoxy resin composition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for60 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 15, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 7.0×10³ to 2.3×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling. It also hadgood drapability as evaluated by the prepreg drapability evaluationprocedure described in (10). In addition, this prepreg had a glasstransition temperature of 9.8° C. and the epoxy resin composition in theprepreg had a degree of conversion of 5.1%. Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of205° C. as measured according to the procedure described in (13).

Examples 10 and 11

Except for changing the heat-treatment time of the prepreg precursor asspecified in Table 2, the same procedure as in Example 9 was carried outto prepare a prepreg.

As shown in Table 15, the prepreg prepared in Example 10, whichcontained a surface resin having a G′ value in the range of 1.7×10⁴ to7.0×10⁶ Pa as measured at a temperature of 40° C. and an angularfrequency in the range of 0.06 to 314 rad/s, had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling. It also hadan acceptable level of drapability as evaluated by the prepregdrapability evaluation procedure described in (10). Furthermore, theprepreg prepared in Example 11, which contained a surface resin having aG′ value in the range of 2.6×10⁴ to 4.1×10⁷ Pa as measured at atemperature of 40° C. and an angular frequency in the range of 0.06 to314 rad/s, had particularly good dry property and also had a permissiblelevel of drapability although a little worse compared with Examples 9and 10. Other measurement results are shown in Table 15. Furthermore,the mass ratio among the constituents of the component [B] in theprepreg that included a preliminary reaction product as calculated bythe procedure described in (7) showed no change from the mass ratiobased on the contents of the constituents of the component [B] beforethe preliminary reaction.

Example 12

An epoxy resin composition 1 was prepared by mixing 50 parts of jER® 630and 50 parts of Sumiepoxy® ELM434 as the component [B], 5 parts ofSeikacure-S and 40 parts of 3,3′-DAS as the component [C] and 15 partsof Sumikaexcel® PES5003P as the component [D] according to the epoxyresin composition preparation procedure described in (1).

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin composition 1 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for90 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 15, the prepreg prepared contained a surface resinhaving a storage elastic modulus G′ in the range of 6.2×10³ to 1.6×10⁶Pa as measured at a temperature of 40° C. and an angular frequency inthe range of 0.06 to 314 rad/s, had a particularly good dry property asevaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9), with no surface resin remaining on themetal plate after removal by pulling, and also had good drapability asevaluated by the prepreg drapability evaluation procedure described in(10). In addition, this prepreg had a glass transition temperature of9.5° C. and the epoxy resin composition in the prepreg had a degree ofconversion of 8.5%. Furthermore, the mass ratio among the constituentsof the component [B] in the prepreg that included a preliminary reactionproduct as calculated by the procedure described in (7) showed no changefrom the mass ratio based on the contents of the constituents of thecomponent [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of190° C. as measured according to the procedure described in (13).

Examples 13 and 14

Except for changing the heat-treatment time of the prepreg precursor asspecified in Table 2, the same procedure as in Example 12 was carriedout to prepare a prepreg.

As shown in Table 15, the prepreg prepared in Example 13, whichcontained a surface resin having a G′ value in the range of 8.8×10³ to6.8×10⁶ Pa as measured at a temperature of 40° C. and an angularfrequency in the range of 0.06 to 314 rad/s, had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling. It also hadan acceptable level of drapability as evaluated by the prepregdrapability evaluation procedure described in (10). Furthermore, theprepreg prepared in Example 14, which contained a surface resin having aG′ value in the range of 2.3×10⁴ to 3.8×10⁷ Pa as measured at atemperature of 40° C. and an angular frequency in the range of 0.06 to314 rad/s, had particularly good dry property and also had a permissiblelevel of drapability although a little worse compared with Examples 12and 13. Other measurement results are shown in Table 15. Furthermore,the mass ratio among the constituents of the component [B] in theprepreg that included a preliminary reaction product as calculated bythe procedure described in (7) showed no change from the mass ratiobased on the contents of the constituents of the component [B] beforethe preliminary reaction.

Example 15

An epoxy resin composition 1 was prepared by mixing 50 parts ofARALDITE® MY0600 and 50 parts of jER® 825 as the component [B], 35 partsof 3,3′-DAS as the component [C], and 35 parts of Virantage® VW-10700RPas the component [D] according to the epoxy resin compositionpreparation procedure described in (1). Then, 25 parts of Orgasol® 1002DNat 1 adopted as the component [E] was added to the epoxy resincomposition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for90 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 15, the prepreg prepared contained a surface resinhaving a storage elastic modulus G′ in the range of 6.1×10³ to 1.5×10⁶Pa as measured at a temperature of 40° C. and an angular frequency inthe range of 0.06 to 314 rad/s, had a particularly good dry property asevaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9), with no surface resin remaining on themetal plate after removal by pulling, and also had good drapability asevaluated by the prepreg drapability evaluation procedure described in(10). In addition, this prepreg had a glass transition temperature of8.8° C. and the epoxy resin composition in the prepreg had a degree ofconversion of 7.2%. Furthermore, the mass ratio among the constituentsof the component [B] in the prepreg that included a preliminary reactionproduct as calculated by the procedure described in (7) showed no changefrom the mass ratio based on the contents of the constituents of thecomponent [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of185° C. as measured according to the procedure described in (13).

Examples 16 and 17

Except for changing the heat-treatment time of the prepreg precursor asspecified in Table 2, the same procedure as in Example 15 was carriedout to prepare a prepreg.

As shown in Table 15, the prepreg prepared in Example 16, whichcontained a surface resin having a G′ value in the range of 8.0×10³ to5.1×10⁶ Pa as measured at a temperature of 40° C. and an angularfrequency in the range of 0.06 to 314 rad/s, had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling. It also hadan acceptable level of drapability as evaluated by the prepregdrapability evaluation procedure described in (10). Furthermore, theprepreg prepared in Example 17, which contained a surface resin having aG′ value in the range of 2.8×10⁴ to 2.1×10⁷ Pa as measured at atemperature of 40° C. and an angular frequency in the range of 0.06 to314 rad/s, had particularly good dry property and also had a permissiblelevel of drapability although a little worse compared with Examples 15and 16. Other measurement results are shown in Table 15. Furthermore,the mass ratio among the constituents of the component [B] in theprepreg that included a preliminary reaction product as calculated bythe procedure described in (7) showed no change from the mass ratiobased on the contents of the constituents of the component [B] beforethe preliminary reaction.

Example 18

An epoxy resin composition was prepared by mixing 50 parts of jER® 630and 50 parts of jER® 807 as the component [B], 20 parts of Seikacure-Sas the component [C], and 20 parts of Sumikaexcel® PES5003P and 45 partsof Virantage® VW-10700RP as the component [D] according to the epoxyresin composition preparation procedure described in (1).

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin composition prepared above, a prepreg precursor was producedaccording to the prepreg precursor preparation procedure described in(3). The resulting prepreg precursor was heat-treated for 30 hoursaccording to the prepreg precursor heat-treatment procedure described in(5) to allow the preliminary reaction product of [B] and [C] to becontained in the prepreg.

As shown in Table 16, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 2.2×10³ to 1.3×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had good dry property asevaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9) and there was no surface resin remainingon the metal plate after removal by pulling. It had particularly gooddrapability as evaluated by the prepreg drapability evaluation proceduredescribed in (10). The prepreg had a glass transition temperature of5.3° C. as measured by the prepreg's glass transition temperaturemeasurement procedure described in (4) and the epoxy resin compositionin the prepreg had a degree of conversion of 1.5% as measured by theepoxy resin composition's degree of conversion measurement proceduredescribed in (8). Furthermore, the mass ratio among the constituents ofthe component [B] in the prepreg that included a preliminary reactionproduct as calculated by the procedure described in (7) showed no changefrom the mass ratio based on the contents of the constituents of thecomponent [B] before the preliminary reaction.

In addition, the cured prepreg cured by the prepreg curing proceduredescribed in (12) had a glass transition temperature of 205° C. asmeasured according to the procedure described in (13). Furthermore,electron microscopic observation showed that the cured prepreg had asea-island type phase-separated structure.

Examples 19 to 22

Except for changing the heat-treatment time of the prepreg precursor asspecified in Table 3, the same procedure as in Example 18 was carriedout to prepare a prepreg.

As shown in Table 16, the prepreg prepared in Example 19, whichcontained a surface resin having a G′ value in the range of 6.5×10³ to2.1×10⁶ Pa as measured at a temperature of 40° C. and an angularfrequency in the range of 0.06 to 314 rad/s, had a particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9), with no surface resinremaining on the metal plate after removal by pulling, and also had gooddrapability as evaluated by the prepreg drapability evaluation proceduredescribed in (10). Furthermore, the prepreg prepared in Example 20,which contained a surface resin having a G′ value in the range of1.4×10⁴ to 5.8×10⁶ Pa as measured at a temperature of 40° C. and anangular frequency in the range of 0.06 to 314 rad/s, had particularlygood dry property as evaluated based on measurements of the tackinessbetween prepreg and metal taken as described in (9) and there was nosurface resin remaining on the metal plate after removal by pulling. Thedrapability as evaluated by the prepreg drapability evaluation procedurewas at an acceptable level although slightly lower than in Example 19.Furthermore, the prepregs prepared in Examples 21 and 22, eachcontaining a surface resin having a G′ value in the range of 1.0×10³ to2.0×10⁸ Pa as measured at a temperature of 40° C. and an angularfrequency in the range of 0.06 to 314 rad/s, had particularly good dryproperty and also had a permissible level of drapability although alittle worse compared with Examples 18 to 20. Furthermore, the massratio among the constituents of the component [B] in the prepreg thatincluded a preliminary reaction product as calculated by the proceduredescribed in (7) showed no change from the mass ratio based on thecontents of the constituents of the component [B] before the preliminaryreaction. Other measurement results are shown in Table 16.

Furthermore, electron microscopic observation showed that the curedprepreg produced by curing the prepreg of Example 19 to 22 had asea-island type phase-separated structure.

Example 23

An epoxy resin composition was prepared by mixing 50 parts of ARALDITE®MY0600 and 50 parts of jER® 825 as the component [B], 20 parts of3,3′-DAS as the component [C], and 20 parts of Sumikaexcel® PES5003P and45 parts of Virantage® VW-10700RP as the component [D] according to theepoxy resin composition preparation procedure described in (1).

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin composition prepared above, a prepreg precursor was producedaccording to the prepreg precursor preparation procedure described in(3). The resulting prepreg precursor was heat-treated for 60 hoursaccording to the prepreg precursor heat-treatment procedure described in(5) to allow the preliminary reaction product of [B] and [C] to becontained in the prepreg.

As shown in Table 16, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 5.5×10³ to 1.1×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling. It had gooddrapability as evaluated by the prepreg drapability evaluation proceduredescribed in (10). The prepreg had a glass transition temperature of10.4° C. as measured by the prepreg's glass transition temperaturemeasurement procedure described in (4) and the epoxy resin compositionin the prepreg had a degree of conversion of 3.7% as measured by theepoxy resin composition's degree of conversion measurement proceduredescribed in (8). Furthermore, the mass ratio among the constituents ofthe component [B] in the prepreg that included a preliminary reactionproduct as calculated by the procedure described in (7) showed no changefrom the mass ratio based on the contents of the constituents of thecomponent [B] before the preliminary reaction.

In addition, the cured prepreg cured by the prepreg curing proceduredescribed in (12) had a glass transition temperature of 185° C. asmeasured according to the procedure described in (13). Furthermore,electron microscopic observation showed that the cured prepreg had asea-island type phase-separated structure.

Examples 24 and 25

Except for changing the heat-treatment time of the prepreg precursor asspecified in Table 3, the same procedure as in Example 23 was carriedout to prepare a prepreg.

As shown in Table 16, the prepreg prepared in Example 24, whichcontained a surface resin having a G′ value in the range of 9.4×10³ to4.8×10⁶ Pa as measured at a temperature of 40° C. and an angularfrequency in the range of 0.06 to 314 rad/s, had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling. It also hadan acceptable level of drapability as evaluated by the prepregdrapability evaluation procedure described in (10). Furthermore, theprepreg prepared in Example 25, which contained a surface resin having aG′ value in the range of 4.2×10⁴ to 3.3×10⁷ Pa as measured at atemperature of 40° C. and an angular frequency in the range of 0.06 to314 rad/s, had particularly good dry property and also had a permissiblelevel of drapability although a little worse compared with Examples 23and 24. Furthermore, the mass ratio among the constituents of thecomponent [B] in the prepreg that included a preliminary reactionproduct as calculated by the procedure described in (7) showed no changefrom the mass ratio based on the contents of the constituents of thecomponent [B] before the preliminary reaction. Other measurement resultsare shown in Table 16.

Furthermore, electron microscopic observation showed that the curedprepreg produced by curing the prepreg of Example 24 and 25 had asea-island type phase-separated structure.

Example 26

An epoxy resin composition was prepared by mixing 50 parts of jER® 630and 50 parts of jER® 807 as the component [B], 20 parts of Seikacure-Sas the component [C], and 20 parts of Sumikaexcel® PES5003P and 45 partsof Virantage® VW-10700RP as the component [D] according to the epoxyresin composition preparation procedure described in (1).

Using the epoxy resin composition prepared above, a resin film 1 wasprepared according to the prepreg precursor preparation proceduredescribed in (3). The resin film 1 prepared above was heat-treated for30 hours in a similar way to the prepreg precursor heat-treatmentprocedure described in (5) to provide a resin film 1′ that included apreliminary reaction product of [B] and [C].

Furthermore, when a prepreg is prepared using Torayca® T800S-24K-10E asthe component [A] according to the prepreg precursor preparationprocedure described in (3), an impregnated first prepreg was sandwichedbetween the resin films 1 and 1′ to provide a prepreg having the resinfilm 1 as one surface resin and the resin film 1′ as the other surfaceresin.

As shown in Table 17, the surface resin in the prepreg prepared abovethat was higher in G′ had a G′ value in the range of 2.2×10³ to 1.3×10⁶Pa as measured at a temperature of 40° C. and an angular frequency inthe range of 0.06 to 314 rad/s. The prepreg had good dry property asevaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9) and there was no surface resin remainingon the metal plate after removal by pulling. It had particularly gooddrapability as evaluated by the prepreg drapability evaluation proceduredescribed in (10). The prepreg had a glass transition temperature of3.9° C. as measured by the prepreg's glass transition temperaturemeasurement procedure described in (4) and the epoxy resin compositionin the prepreg had a degree of conversion of 0.8% as measured by theepoxy resin composition's degree of conversion measurement proceduredescribed in (8). Furthermore, the mass ratio among the constituents ofthe component [B] in the prepreg that included a preliminary reactionproduct as calculated by the procedure described in (7) showed no changefrom the mass ratio based on the contents of the constituents of thecomponent [B] before the preliminary reaction.

In addition, the cured prepreg cured by the prepreg curing proceduredescribed in (12) had a glass transition temperature of 205° C. asmeasured according to the procedure described in (13). Electronmicroscopic observation showed that the cured prepreg had a sea-islandtype phase-separated structure.

Here, a polypropylene cover film with a thickness of 50 μm was stuck onthe surface of the prepreg's surface resin that was the lower in G′ andresults showed good sticking property.

Example 27

Except that the resin film 1 was heat-treated for 60 hours instead of 30hours when producing the resin film 1, the same procedure as in Example26 was carried out to prepare a prepreg.

As shown in Table 17, the surface resin in the prepreg prepared abovethat was higher in G′ had a G′ value in the range of 6.5×10³ to 2.1×10⁶Pa as measured at a temperature of 40° C. and an angular frequency inthe range of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling. It also hadparticularly good drapability as evaluated by the prepreg drapabilityevaluation procedure described in (10). The prepreg had a glasstransition temperature of 6.4° C. as measured by the prepreg's glasstransition temperature measurement procedure described in (4) and theepoxy resin composition in the prepreg had a degree of conversion of1.6% as measured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the cured prepreg cured by the prepreg curing proceduredescribed in (12) had a glass transition temperature of 205° C. asmeasured according to the procedure described in (13). Electronmicroscopic observation showed that the cured prepreg had a sea-islandtype phase-separated structure.

Here, a polypropylene cover film with a thickness of 50 μm was stuck onthe surface of the prepreg's surface resin that was the lower in G′ andresults showed good sticking property.

Example 28

Except that the resin film 1 was heat-treated for 30 hours or 60 hoursto prepare two resin films 1′ and 1″ that differed in the content of thepreliminary reaction product and that they were used to sandwich animpregnated first prepreg, the same procedure as in Example 26 wascarried out to prepare a prepreg.

As shown in Table 17, the surface resin in the prepreg prepared abovethat was higher in G′ had a G′ value in the range of 6.5×10³ to 2.1×10⁶Pa as measured at a temperature of 40° C. and an angular frequency inthe range of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling. It also hadgood drapability as evaluated by the prepreg drapability evaluationprocedure described in (10). The prepreg had a glass transitiontemperature of 8.5° C. as measured by the prepreg's glass transitiontemperature measurement procedure described in (4) and the epoxy resincomposition in the prepreg had a degree of conversion of 2.5% asmeasured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the cured prepreg cured by the prepreg curing proceduredescribed in (12) had a glass transition temperature of 205° C. asmeasured according to the procedure described in (13). Furthermore,electron microscopic observation showed that the cured prepreg had asea-island type phase-separated structure.

Here, a polypropylene cover film with a thickness of 50 μm was stuck onthe surface of the prepreg's surface resin that was the lower in G′ andresults showed a slight deterioration in sticking property though it isstill at an acceptable level.

Example 29

An epoxy resin composition 1 was prepared by mixing 25 parts of Denacol®EX-731, 60 parts of Sumiepoxy® ELM434, and 15 parts of jER® 825 as thecomponent [B], 40 parts of Seikacure-S as the component [C], and 10parts of Sumikaexcel® PES5003P as the component [D] according to theepoxy resin composition preparation procedure described in (1). Then, 20parts of Orgasol® 1002D Nat 1 adopted as the component [E] was added tothe epoxy resin composition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for30 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 17, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 1.4×10³ to 1.5×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had an acceptable level of dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9). It had good drapability asevaluated by the prepreg drapability evaluation procedure described in(10). The prepreg had a glass transition temperature of 5.3° C. asmeasured by the prepreg's glass transition temperature measurementprocedure described in (4) and the epoxy resin composition in theprepreg had a degree of conversion of 2.3% as measured by the epoxyresin composition's degree of conversion measurement procedure describedin (8). Furthermore, the mass ratio among the constituents of thecomponent [B] in the prepreg that included a preliminary reactionproduct as calculated by the procedure described in (7) showed no changefrom the mass ratio based on the contents of the constituents of thecomponent [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of182° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,920 MPa as measured according to (15).

Examples 30 and 31

Except for changing the heat-treatment time of the prepreg precursor asspecified in Table 4, the same procedure as in Example 29 was carriedout to prepare a prepreg.

As shown in Table 17, the prepreg prepared in Example 30, whichcontained a surface resin having a G′ value in the range of 4.7×10³ to3.8×10⁶ Pa as measured at a temperature of 40° C. and an angularfrequency in the range of 0.06 to 314 rad/s, had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling. It also hadgood drapability as evaluated by the prepreg drapability evaluationprocedure described in (10).

Furthermore, the prepreg prepared in Example 31, which contained asurface resin having a G′ value in the range of 1.1×10⁴ to 5.0×10⁷ Pa asmeasured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s, had particularly good dry property and therewas no surface resin remaining on the metal plate after removal bypulling. In addition, the drapability was at an acceptable levelalthough a little worse compared with Examples 29 and 30. Furthermore,the mass ratio among the constituents of the component [B] in theprepreg that included a preliminary reaction product as calculated bythe procedure described in (7) showed no change from the mass ratiobased on the contents of the constituents of the component [B] beforethe preliminary reaction.

Furthermore, in both Examples 30 and 31, the carbon fiber reinforcedmaterial had the same level of 0° tensile strength as in Example 29 asmeasured according to (15). Other measurement results are shown in Table17.

Example 32

An epoxy resin composition 1 was prepared by mixing 25 parts of Denacol®EX-731, 60 parts of Sumiepoxy® ELM434, and 15 parts of jER® 825 as thecomponent [B], 40 parts of Seikacure-S as the component [C], and 10parts of Sumikaexcel® PES5003P as the component [D] according to theepoxy resin composition preparation procedure described in (1). Then, 20parts of Orgasol® 1002D Nat 1 adopted as the component [E] was added tothe epoxy resin composition 1 to prepare an epoxy resin composition 2.

Using the epoxy resin composition 2 prepared above, a resin film 2 wasprepared according to the prepreg precursor preparation proceduredescribed in (3). The resin film 2 prepared above was heat-treated for30 hours in a similar way to the prepreg precursor heat-treatmentprocedure described in (5) to provide a resin film 2′ that included apreliminary reaction product of [B] and [C].

Furthermore, when a prepreg is prepared using Torayca® T800S-24K-10E asthe component [A] according to the prepreg precursor preparationprocedure described in (3), an impregnated first prepreg was sandwichedbetween the resin films 2 and 2′ to provide a prepreg having the resinfilm 2 as one surface resin and the resin film 2′ as the other surfaceresin.

As shown in Table 17, the surface resin in the prepreg prepared abovethat was higher in G′ had a G′ value in the range of 1.4×10³ to 1.5×10⁶Pa as measured at a temperature of 40° C. and an angular frequency inthe range of 0.06 to 314 rad/s. The prepreg had an acceptable level ofdry property as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9). Furthermore, it hadparticularly good drapability as evaluated by the prepreg drapabilityevaluation procedure described in (10). The prepreg had a glasstransition temperature of 3.5° C. as measured by the prepreg's glasstransition temperature measurement procedure described in (4) and theepoxy resin composition in the prepreg had a degree of conversion of1.3% as measured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of182° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,920 MPa as measured according to (15).

A polypropylene cover film with a thickness of 50 μm was stuck on thesurface of the prepreg's surface resin that was the lower in G′ andresults showed good sticking property.

Example 33

Except that the resin film 2 was heat-treated for 75 hours instead of 30hours when producing the resin film 2, the same procedure as in Example32 was carried out to prepare a prepreg.

As shown in Table 17, the surface resin in the prepreg prepared abovethat was higher in G′ had a G′ value in the range of 4.7×10³ to 3.8×10⁶Pa as measured at a temperature of 40° C. and an angular frequency inthe range of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had good drapability as evaluated by the prepregdrapability evaluation procedure described in (10). The prepreg had aglass transition temperature of 5.8° C. as measured by the prepreg'sglass transition temperature measurement procedure described in (4) andthe epoxy resin composition in the prepreg had a degree of conversion of3.7% as measured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of182° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,910 MPa as measured according to (15).

Here, a polypropylene cover film with a thickness of 50 μm was stuck onthe surface of the prepreg's surface resin that was lower in G′ andresults showed good sticking property.

Example 34

Except that the resin film 2 was heat-treated for 30 hours or 75 hoursto prepare two resin films 2′ and 2″ that differed in the content of thepreliminary reaction product and that they were used to sandwich animpregnated first prepreg, the same procedure as in Example 32 wascarried out to prepare a prepreg.

As shown in Table 18, the surface resin in the prepreg prepared abovethat was higher in G′ had a G′ value in the range of 4.7×10³ to 3.8×10⁶Pa as measured at a temperature of 40° C. and an angular frequency inthe range of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had good drapability as evaluated by the prepregdrapability evaluation procedure described in (10). The prepreg had aglass transition temperature of 7.7° C. as measured by the prepreg'sglass transition temperature measurement procedure described in (4) andthe epoxy resin composition in the prepreg had a degree of conversion of4.4% as measured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8).

Furthermore, the mass ratio among the constituents of the component [B]in the prepreg that included a preliminary reaction product ascalculated by the procedure described in (7) showed no change from themass ratio based on the contents of the constituents of the component[B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of182° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,920 MPa as measured according to (15).

Here, a polypropylene cover film with a thickness of 50 μm was stuck onthe surface of the prepreg's surface resin that was lower in G′ andresults showed a slight deterioration in sticking property though it isstill at an acceptable level.

Example 35

Except for using 5 parts, instead of 25 parts, of Denacol® EX-731 and 35parts, instead of 15 parts, of jER® 825 as the component [B], the sameprocedure as in Example 30 was carried out to prepare a prepreg.

As shown in Table 18, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 2.8×10³ to 2.3×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had good dry property asevaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9) and there was no surface resin remainingon the metal plate after removal by pulling. Furthermore, it also hadgood drapability as evaluated by the prepreg drapability evaluationprocedure described in (10). The prepreg had a glass transitiontemperature of 8.9° C. as measured by the prepreg's glass transitiontemperature measurement procedure described in (4) and the epoxy resincomposition in the prepreg had a degree of conversion of 7.3% asmeasured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of198° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,780 MPa as measured according to (15), which was a littlesmaller than in Example 30.

Example 36

Except for using 10 parts, instead of 25 parts, of Denacol® EX-731 and30 parts, instead of 15 parts, of jER® 825 as the component [B], thesame procedure as in Example 30 was carried out to prepare a prepreg.

As shown in Table 18, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 3.8×10³ to 3.0×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had good dry property asevaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9) and there was no surface resin remainingon the metal plate after removal by pulling. Furthermore, it also hadgood drapability as evaluated by the prepreg drapability evaluationprocedure described in (10). The prepreg had a glass transitiontemperature of 9.7° C. as measured by the prepreg's glass transitiontemperature measurement procedure described in (4) and the epoxy resincomposition in the prepreg had a degree of conversion of 7.4% asmeasured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of191° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,840 MPa as measured according to (15), which was slightlysmaller than in Example 30.

Examples 37 and 38

Except for using 15 parts or 20 parts, instead of 10 parts, ofSumikaexcel® PES5003P as the component [D], the same procedure as inExample 30 was carried out to prepare a prepreg.

As shown in Table 18, the prepreg prepared in Example 37, whichcontained a surface resin having a G′ value in the range of 1.4×10⁴ to1.1×10⁷ Pa as measured at a temperature of 40° C. and an angularfrequency in the range of 0.06 to 314 rad/s, and the prepreg prepared inExample 38, which contained a surface resin having a G′ value in therange of 3.7×10⁴ to 3.1×10⁷ Pa, had particularly good dry property asevaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9) and there was no surface resin remainingon the metal plate after removal by pulling. Furthermore, thedrapability as evaluated by the prepreg drapability evaluation proceduredescribed in (10) was at an acceptable level although slightly lowerthan in Example 30. Furthermore, the mass ratio among the constituentsof the component [B] in the prepreg that included a preliminary reactionproduct as calculated by the procedure described in (7) showed no changefrom the mass ratio based on the contents of the constituents of thecomponent [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of182° C. or 183° C. as measured according to the procedure described in(13). Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 3,080 MPa or 3,220 MPa as measured according to (15), whichwere larger than in Example 30.

Example 39

Except for using 45 parts, instead of 60 parts, of Sumiepoxy® ELM434 and30 parts, instead of 15 parts, of jER® 825 as the component [C], thesame procedure as in Example 30 was carried out to prepare a prepreg.

As shown in Table 18, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 3.3×10³ to 2.1×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had good dry property asevaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9) and there was no surface resin remainingon the metal plate after removal by pulling. Furthermore, it also hadgood drapability as evaluated by the prepreg drapability evaluationprocedure described in (10). The prepreg had a glass transitiontemperature of 9.3° C. as measured by the prepreg's glass transitiontemperature measurement procedure described in (4) and the epoxy resincomposition in the prepreg had a degree of conversion of 7.3% asmeasured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of175° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,990 MPa as measured according to (15), which was slightlylarger than in Example 30.

Example 40

An epoxy resin composition 1 was prepared by mixing 30 parts of Denacol®EX-731 and 70 parts of Sumiepoxy® ELM434 as the component [B], 44 partsof Seikacure-S as the component [C], and 10 parts of Sumikaexcel®PES5003P as the component [D] according to the epoxy resin compositionpreparation procedure described in (1). Then, 20 parts of Orgasol® 1002DNat 1 adopted as the component [E] was added to the epoxy resincomposition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for75 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 18, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 1.1×10⁴ to 9.8×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had an acceptable level of drapability as evaluatedby the prepreg drapability evaluation procedure described in (10). Theprepreg had a glass transition temperature of 11.1° C. as measured bythe prepreg's glass transition temperature measurement proceduredescribed in (4) and the epoxy resin composition in the prepreg had adegree of conversion of 7.2% as measured by the epoxy resincomposition's degree of conversion measurement procedure described in(8). Furthermore, the mass ratio among the constituents of the component[B] in the prepreg that included a preliminary reaction product ascalculated by the procedure described in (7) showed no change from themass ratio based on the contents of the constituents of the component[B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of181° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,900 MPa as measured according to (15).

Example 41

An epoxy resin composition 1 was prepared by mixing 20 parts of Denacol®EX-731 and 80 parts of Sumiepoxy® ELM434 as the component [B], 44 partsof Seikacure-S as the component [C], and 10 parts of Sumikaexcel®PES5003P as the component [D] according to the epoxy resin compositionpreparation procedure described in (1). Then, 20 parts of Orgasol® 1002DNat 1 adopted as the component [E] was added to the epoxy resincomposition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for75 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 18, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 9.8×10³ to 9.5×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had good drapability as evaluated by the prepregdrapability evaluation procedure described in (10). The prepreg had aglass transition temperature of 10.8° C. as measured by the prepreg'sglass transition temperature measurement procedure described in (4) andthe epoxy resin composition in the prepreg had a degree of conversion of7.0% as measured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of188° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,790 MPa as measured according to (15).

Example 42

An epoxy resin composition 1 was prepared by mixing 30 parts of GAN, 60parts of Sumiepoxy® ELM434, and 10 parts of jER® 825 as the component[B], 45 parts of Seikacure-S as the component [C], and 10 parts ofSumikaexcel® PES5003P as the component [D] according to the epoxy resincomposition preparation procedure described in (1). Then, 20 parts ofOrgasol® 1002D Nat 1 adopted as the component [E] was added to the epoxyresin composition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for30 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 19, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 1.0×10³ to 7.0×10⁵ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had an acceptable level of dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9). Furthermore, it hadparticularly good drapability as evaluated by the prepreg drapabilityevaluation procedure described in (10). The prepreg had a glasstransition temperature of 4.2° C. as measured by the prepreg's glasstransition temperature measurement procedure described in (4) and theepoxy resin composition in the prepreg had a degree of conversion of2.0% as measured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of190° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,800 MPa as measured according to (15).

Examples 43 and 44

Except for changing the heat-treatment time of the prepreg precursor asspecified in Table 6, the same procedure as in Example 42 was carriedout to prepare a prepreg.

As shown in Table 19, the prepreg prepared in Example 43, whichcontained a surface resin having a G′ value in the range of 3.6×10³ to1.6×10⁶ Pa as measured at a temperature of 40° C. and an angularfrequency in the range of 0.06 to 314 rad/s, had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had good drapability as evaluated by the prepregdrapability evaluation procedure described in (10).

Furthermore, the prepreg prepared in Example 44, which contained asurface resin having a G′ value in the range of 8.4×10³ to 2.3×10⁷ Pa asmeasured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s, had particularly good dry property and therewas no surface resin remaining on the metal plate after removal bypulling. In addition, the drapability was at an acceptable levelalthough slightly worse compared with Examples 42 and 43. Furthermore,the mass ratio among the constituents of the component [B] in theprepreg that included a preliminary reaction product as calculated bythe procedure described in (7) showed no change from the mass ratiobased on the contents of the constituents of the component [B] beforethe preliminary reaction.

Furthermore, in both Examples 43 and 44, the carbon fiber reinforcedmaterial had the same level of 0° tensile strength as in Example 42 asmeasured according to (15). Other measurement results are shown in Table19.

Example 45

An epoxy resin composition 1 was prepared by mixing 30 parts of GAN, 60parts of Sumiepoxy® ELM434, and 10 parts of jER® 825 as the component[B], 45 parts of Seikacure-S as the component [C], and 10 parts ofSumikaexcel® PES5003P as the component [D] according to the epoxy resincomposition preparation procedure described in (1). Then, 20 parts ofOrgasol® 1002D Nat 1 adopted as the component [E] was added to the epoxyresin composition 1 to prepare an epoxy resin composition 2.

Using the epoxy resin composition 2 prepared above, a resin film 2 wasprepared according to the prepreg precursor preparation proceduredescribed in (3). The resin film 2 prepared above was heat-treated for30 hours in a similar way to the prepreg precursor heat-treatmentprocedure described in (5) to provide a resin film 2′ that included apreliminary reaction product of [B] and [C].

Furthermore, when a prepreg is prepared using Torayca® T800S-24K-10E asthe component [A] according to the prepreg precursor preparationprocedure described in (3), an impregnated first prepreg was sandwichedbetween the resin films 2 and 2′ to provide a prepreg having the resinfilm 2 as one surface resin and the resin film 2′ as the other surfaceresin.

As shown in Table 19, the surface resin in the prepreg prepared abovethat was higher in G′ had a G′ value in the range of 1.0×10³ to 7.0×10⁵Pa as measured at a temperature of 40° C. and an angular frequency inthe range of 0.06 to 314 rad/s. The prepreg had an acceptable level ofdry property as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9). Furthermore, it hadparticularly good drapability as evaluated by the prepreg drapabilityevaluation procedure described in (10). The prepreg had a glasstransition temperature of 3.2° C. as measured by the prepreg's glasstransition temperature measurement procedure described in (4) and theepoxy resin composition in the prepreg had a degree of conversion of1.1% as measured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of190° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,810 MPa as measured according to (15).

A polypropylene cover film with a thickness of 50 μm was stuck on thesurface of the prepreg's surface resin that was the lower in G′ andresults showed good sticking property.

Example 46

Except that the resin film 2 was heat-treated for 75 hours instead of 30hours when producing the resin film 2, the same procedure as in Example45 was carried out to prepare a prepreg.

As shown in Table 19, the surface resin in the prepreg prepared abovethat was higher in G′ had a G′ value in the range of 3.6×10³ to 1.6×10⁶Pa as measured at a temperature of 40° C. and an angular frequency inthe range of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had good drapability as evaluated by the prepregdrapability evaluation procedure described in (10). The prepreg had aglass transition temperature of 5.5° C. as measured by the prepreg'sglass transition temperature measurement procedure described in (4) andthe epoxy resin composition in the prepreg had a degree of conversion of3.3% as measured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of190° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,820 MPa as measured according to (15).

Here, a polypropylene cover film with a thickness of 50 μm was stuck onthe surface of the prepreg's surface resin that was lower in G′ andresults showed good sticking property.

Example 47

Except that the resin film 2 was heat-treated for 30 hours or 75 hoursto prepare two resin films 2′ and 2″ that differed in the content of thepreliminary reaction product and that they were used to sandwich animpregnated first prepreg, the same procedure as in Example 45 wascarried out to prepare a prepreg.

As shown in Table 19, the surface resin in the prepreg prepared abovethat was higher in G′ had a G′ value in the range of 3.6×10³ to 1.6×10⁶Pa as measured at a temperature of 40° C. and an angular frequency inthe range of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had good drapability as evaluated by the prepregdrapability evaluation procedure described in (10). The prepreg had aglass transition temperature of 7.5° C. as measured by the prepreg'sglass transition temperature measurement procedure described in (4) andthe epoxy resin composition in the prepreg had a degree of conversion of4.3% as measured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of190° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,820 MPa as measured according to (15).

Here, a polypropylene cover film with a thickness of 50 μm was stuck onthe surface of the prepreg's surface resin that was lower in G′ andresults showed a slight deterioration in sticking property though it isstill at an acceptable level.

Example 48

Except for using 5 parts, instead of 30 parts, of GAN and 35 parts,instead of 10 parts, of jER® 825 as the component [B], the sameprocedure as in Example 43 was carried out to prepare a prepreg.

As shown in Table 19, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 4.8×10³ to 2.3×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had good drapability as evaluated by the prepregdrapability evaluation procedure described in (10). The prepreg had aglass transition temperature of 9.9° C. as measured by the prepreg'sglass transition temperature measurement procedure described in (4) andthe epoxy resin composition in the prepreg had a degree of conversion of7.3% as measured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of204° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,670 MPa as measured according to (15), which was slightlysmaller than in Example 43.

Example 49

Except for using 20 parts, instead of 30 parts, of GAN and 20 parts,instead of 10 parts, of jER® 825 as the component [B], the sameprocedure as in Example 43 was carried out to prepare a prepreg.

As shown in Table 19, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 4.1×10³ to 2.0×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had good drapability as evaluated by the prepregdrapability evaluation procedure described in (10). The prepreg had aglass transition temperature of 9.3° C. as measured by the prepreg'sglass transition temperature measurement procedure described in (4) andthe epoxy resin composition in the prepreg had a degree of conversion of7.4% as measured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of196° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,750 MPa as measured according to (15), which was slightlysmaller than in Example 43.

Examples 50 and 51

Except for using 15 parts or 20 parts, instead of 10 parts, ofSumikaexcel® PES5003P as the component [D], the same procedure as inExample 43 was carried out to prepare a prepreg.

As shown in Table 20, the prepreg prepared in Example 50, whichcontained a surface resin having a G′ value in the range of 1.1×10⁴ to5.1×10⁶ Pa as measured at a temperature of 40° C. and an angularfrequency in the range of 0.06 to 314 rad/s, and the prepreg prepared inExample 51, which contained a surface resin having a G′ value in therange of 2.2×10⁴ to 1.2×10⁷ Pa, had particularly good dry property asevaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9) and there was no surface resin remainingon the metal plate after removal by pulling. Furthermore, the prepreg ofExample 50 also had good drapability as evaluated by the prepregdrapability evaluation procedure described in (10). On the other hand,the prepreg of Example 51 had slightly deteriorated drapability althoughit was at an acceptable level. Furthermore, the mass ratio among theconstituents of the component [B] in the prepreg that included apreliminary reaction product as calculated by the procedure described in(7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, in both Examples 50 and 51, the carbon fiber reinforcedmaterial cured by the prepreg curing procedure described in (12) had aglass transition temperature of 190° C. as measured according to theprocedure described in (13). Furthermore, the carbon fiber reinforcedmaterial had a 0° tensile strength of 2,930 MPa or 3,050 MPa as measuredaccording to (15), which were larger than in Example 43.

Example 52

An epoxy resin composition 1 was prepared by mixing 30 parts of GAN, 40parts of Sumiepoxy® ELM434, and 30 parts of jER® 825 as the component[B], 38 parts of Seikacure-S as the component [C], and 10 parts ofSumikaexcel® PES5003P as the component [D] according to the epoxy resincomposition preparation procedure described in (1). Then, 20 parts ofOrgasol® 1002D Nat 1 adopted as the component [E] was added to the epoxyresin composition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for75 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 20, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 2.6×10³ to 9.0×10⁵ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had good dry property asevaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9) and there was no surface resin remainingon the metal plate after removal by pulling. Furthermore, it hadparticularly good drapability as evaluated by the prepreg drapabilityevaluation procedure described in (10). The prepreg had a glasstransition temperature of 3.9° C. as measured by the prepreg's glasstransition temperature measurement procedure described in (4) and theepoxy resin composition in the prepreg had a degree of conversion of7.7% as measured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of178° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,870 MPa as measured according to (15).

Example 53

An epoxy resin composition 1 was prepared by mixing 40 parts of GAN and60 parts of Sumiepoxy® ELM434 as the component [B], 50 parts ofSeikacure-S as the component [C], and 10 parts of Sumikaexcel® PES5003Pas the component [D] according to the epoxy resin compositionpreparation procedure described in (1). Then, 20 parts of Orgasol® 1002DNat 1 adopted as the component [E] was added to the epoxy resincomposition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for75 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 20, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 9.8×10³ to 4.2×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had an acceptable level of drapability as evaluatedby the prepreg drapability evaluation procedure described in (10). Theprepreg had a glass transition temperature of 10.3° C. as measured bythe prepreg's glass transition temperature measurement proceduredescribed in (4) and the epoxy resin composition in the prepreg had adegree of conversion of 7.6% as measured by the epoxy resincomposition's degree of conversion measurement procedure described in(8). Furthermore, the mass ratio among the constituents of the component[B] in the prepreg that included a preliminary reaction product ascalculated by the procedure described in (7) showed no change from themass ratio based on the contents of the constituents of the component[B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of188° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,780 MPa as measured according to (15).

Example 54

An epoxy resin composition 1 was prepared by mixing 20 parts of GAN and80 parts of Sumiepoxy® ELM434 as the component [B], 50 parts ofSeikacure-S as the component [C], and 10 parts of Sumikaexcel® PES5003Pas the component [D] according to the epoxy resin compositionpreparation procedure described in (1). Then, 20 parts of Orgasol® 1002DNat 1 adopted as the component [E] was added to the epoxy resincomposition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for75 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 20, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 1.2×10⁴ to 4.7×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had an acceptable level of drapability as evaluatedby the prepreg drapability evaluation procedure described in (10). Theprepreg had a glass transition temperature of 10.9° C. as measured bythe prepreg's glass transition temperature measurement proceduredescribed in (4) and the epoxy resin composition in the prepreg had adegree of conversion of 7.8% as measured by the epoxy resincomposition's degree of conversion measurement procedure described in(8). Furthermore, the mass ratio among the constituents of the component[B] in the prepreg that included a preliminary reaction product ascalculated by the procedure described in (7) showed no change from themass ratio based on the contents of the constituents of the component[B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of198° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,700 MPa as measured according to (15).

Example 55

An epoxy resin composition 1 was prepared by mixing 40 parts of TOREP®A-204E and 60 parts of Sumiepoxy® ELM434 as the component [B], 45 partsof 3,3′-DAS as the component [C], and 10 parts of Sumikaexcel® PES5003Pas the component [D] according to the epoxy resin compositionpreparation procedure described in (1). Then, 20 parts of Orgasol® 1002DNat 1 adopted as the component [E] was added to the epoxy resincomposition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for20 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 20, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 1.2×10³ to 7.0×10⁵ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had an acceptable level of dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9). It had good drapability asevaluated by the prepreg drapability evaluation procedure described in(10). The prepreg had a glass transition temperature of 4.4° C. asmeasured by the prepreg's glass transition temperature measurementprocedure described in (4) and the epoxy resin composition in theprepreg had a degree of conversion of 2.2% as measured by the epoxyresin composition's degree of conversion measurement procedure describedin (8).

Furthermore, the mass ratio among the constituents of the component [B]in the prepreg that included a preliminary reaction product ascalculated by the procedure described in (7) showed no change from themass ratio based on the contents of the constituents of the component[B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of192° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,840 MPa as measured according to (15).

Examples 56 and 57

Except for changing the heat-treatment time of the prepreg precursor asspecified in Table 4, the same procedure as in Example 55 was carriedout to prepare a prepreg.

As shown in Table 20, the prepreg prepared in Example 56, whichcontained a surface resin having a G′ value in the range of 4.7×10³ to2.0×10⁶ Pa as measured at a temperature of 40° C. and an angularfrequency in the range of 0.06 to 314 rad/s, had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had good drapability as evaluated by the prepregdrapability evaluation procedure described in (10).

Furthermore, the prepreg prepared in Example 57, which contained asurface resin having a G′ value in the range of 9.2×10³ to 2.6×10⁷ Pa asmeasured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s, had particularly good dry property and therewas no surface resin remaining on the metal plate after removal bypulling. In addition, the drapability was at an acceptable levelalthough slightly worse compared with Examples 55 and 56. Furthermore,the mass ratio among the constituents of the component [B] in theprepreg that included a preliminary reaction product as calculated bythe procedure described in (7) showed no change from the mass ratiobased on the contents of the constituents of the component [B] beforethe preliminary reaction.

Furthermore, in both Examples 56 and 57, the carbon fiber reinforcedmaterial had the same level of 0° tensile strength as in Example 55 asmeasured according to (15). Other measurement results are shown in Table20.

Example 58

An epoxy resin composition 1 was prepared by mixing 40 parts of TOREP®A-204E and 60 parts of Sumiepoxy® ELM434 as the component [B], 45 partsof 3,3′-DAS as the component [C], and 10 parts of Sumikaexcel® PES5003Pas the component [D] according to the epoxy resin compositionpreparation procedure described in (1). Then, 20 parts of Orgasol® 1002DNat 1 adopted as the component [E] was added to the epoxy resincomposition 1 to prepare an epoxy resin composition 2.

Using the epoxy resin composition 2 prepared above, a resin film 2 wasprepared according to the prepreg precursor preparation proceduredescribed in (3). The resin film 2 prepared above was heat-treated for20 hours in a similar way to the prepreg precursor heat-treatmentprocedure described in (5) to provide a resin film 2′ that included apreliminary reaction product of [B] and [C].

Furthermore, when a prepreg is prepared using Torayca® T800S-24K-10E asthe component [A] according to the prepreg precursor preparationprocedure described in (3), an impregnated first prepreg was sandwichedbetween the resin films 2 and 2′ to provide a prepreg having the resinfilm 2 as one surface resin and the resin film 2′ as the other surfaceresin.

As shown in Table 21, the surface resin in the prepreg prepared abovethat was higher in G′ had a G′ value in the range of 1.2×10³ to 7.0×10⁵Pa as measured at a temperature of 40° C. and an angular frequency inthe range of 0.06 to 314 rad/s. The prepreg had an acceptable level ofdry property as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9). Furthermore, it hadparticularly good drapability as evaluated by the prepreg drapabilityevaluation procedure described in (10). The prepreg had a glasstransition temperature of 3.3° C. as measured by the prepreg's glasstransition temperature measurement procedure described in (4) and theepoxy resin composition in the prepreg had a degree of conversion of1.3% as measured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of192° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,840 MPa as measured according to (15).

A polypropylene cover film with a thickness of 50 μm was stuck on thesurface of the prepreg's surface resin that was the lower in G′ andresults showed good sticking property.

Example 59

Except that the resin film 2 was heat-treated for 50 hours instead of 20hours when producing the resin film 2, the same procedure as in Example58 was carried out to prepare a prepreg.

As shown in Table 21, the surface resin in the prepreg prepared abovethat was higher in G′ had a G′ value in the range of 4.7×10³ to 2.0×10⁶Pa as measured at a temperature of 40° C. and an angular frequency inthe range of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had good drapability as evaluated by the prepregdrapability evaluation procedure described in (10). The prepreg had aglass transition temperature of 5.6° C. as measured by the prepreg'sglass transition temperature measurement procedure described in (4) andthe epoxy resin composition in the prepreg had a degree of conversion of3.6% as measured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of192° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,820 MPa as measured according to (15).

Here, a polypropylene cover film with a thickness of 50 μm was stuck onthe surface of the prepreg's surface resin that was lower in G′ andresults showed good sticking property.

Example 60

Except that the resin film 2 was heat-treated for 20 hours or 50 hoursto prepare two resin films 2′ and 2″ that differed in the content of thepreliminary reaction product and that they were used to sandwich animpregnated first prepreg, the same procedure as in Example 58 wascarried out to prepare a prepreg.

As shown in Table 21, the surface resin in the prepreg prepared abovethat was higher in G′ had a G′ value in the range of 4.7×10³ to 2.0×10⁶Pa as measured at a temperature of 40° C. and an angular frequency inthe range of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had good drapability as evaluated by the prepregdrapability evaluation procedure described in (10). The prepreg had aglass transition temperature of 7.6° C. as measured by the prepreg'sglass transition temperature measurement procedure described in (4) andthe epoxy resin composition in the prepreg had a degree of conversion of4.8% as measured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of192° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,830 MPa as measured according to (15).

Here, a polypropylene cover film with a thickness of 50 μm was stuck onthe surface of the prepreg's surface resin that was lower in G′ andresults showed a slight deterioration in sticking property though it isstill at an acceptable level.

Example 61

An epoxy resin composition 1 was prepared by mixing 5 parts of TOREP®A-204E and 60 parts of Sumiepoxy® ELM434 as the component [B], 35 partsof jER® 825 as an epoxy resin other than the components [B] and [C], 45parts of 3,3′-DAS as the component [C] and 10 parts of Sumikaexcel®PES5003P as the component [D] according to the epoxy resin compositionpreparation procedure described in (1). Then, 20 parts of Orgasol® 1002DNat 1 adopted as the component [E] was added to the epoxy resincomposition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for50 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 21, the prepreg prepared contained a surface resinhaving a storage elastic modulus G′ in the range of 5.3×10³ to 2.5×10⁶Pa as measured at a temperature of 40° C. and an angular frequency inthe range of 0.06 to 314 rad/s, had a particularly good dry property asevaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9), with no surface resin remaining on themetal plate after removal by pulling, and also had good drapability asevaluated by the prepreg drapability evaluation procedure described in(10). The prepreg had a glass transition temperature of 10.1° C. asmeasured by the prepreg's glass transition temperature measurementprocedure described in (4) and the epoxy resin composition in theprepreg had a degree of conversion of 8.3% as measured by the epoxyresin composition's degree of conversion measurement procedure describedin (8). Furthermore, the mass ratio among the constituents of thecomponent [B] in the prepreg that included a preliminary reactionproduct as calculated by the procedure described in (7) showed no changefrom the mass ratio based on the contents of the constituents of thecomponent [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of206° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,690 MPa as measured according to (15), which was slightlysmaller than in Example 56.

Example 62

Except for using 25 parts, instead of 5 parts, of TOREP® A-204E and 15parts, instead of 35 parts, of jER® 825 as the component [B], the sameprocedure as in Example 61 was carried out to prepare a prepreg.

As shown in Table 21, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 5.0×10³ to 2.3×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had good drapability as evaluated by the prepregdrapability evaluation procedure described in (10). The prepreg had aglass transition temperature of 9.6° C. as measured by the prepreg'sglass transition temperature measurement procedure described in (4) andthe epoxy resin composition in the prepreg had a degree of conversion of8.4% as measured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of199° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,780 MPa as measured according to (15), which was slightlysmaller than in Example 56.

Examples 63 and 64

Except for using 15 parts or 20 parts, instead of 10 parts, ofSumikaexcel® PES5003P as the component [D], the same procedure as inExample 56 was carried out to prepare a prepreg.

As shown in Table 21, the prepreg prepared in Example 63, whichcontained a surface resin having a G′ value in the range of 1.4×10⁴ to5.9×10⁶ Pa as measured at a temperature of 40° C. and an angularfrequency in the range of 0.06 to 314 rad/s, and the prepreg prepared inExample 64, which contained a surface resin having a G′ value in therange of 2.6×10⁴ to 1.4×10⁷ Pa, had particularly good dry property andthere was no surface resin remaining on the metal plate after removal bypulling. Furthermore, the prepreg of Example 63 also had gooddrapability as evaluated by the prepreg drapability evaluation proceduredescribed in (10) above. On the other hand, the prepreg of Example 64was slightly lower in drapability than in Example 56 although it was atan acceptable level. Furthermore, the mass ratio among the constituentsof the component [B] in the prepreg that included a preliminary reactionproduct as calculated by the procedure described in (7) showed no changefrom the mass ratio based on the contents of the constituents of thecomponent [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of192° C. or 193° C. as measured according to the procedure described in(13). Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,960 MPa or 3,110 MPa as measured according to (15), whichwere larger than in Example 56.

Example 65

An epoxy resin composition 1 was prepared by mixing 40 parts of TOREP®A-204E, 40 parts of Sumiepoxy® ELM434, and 20 parts of jER® 825 as thecomponent [B], 38 parts of 3,3′-DAS as the component [C], and 10 partsof Sumikaexcel® PES5003P as the component [D] according to the epoxyresin composition preparation procedure described in (1). Then, 20 partsof Orgasol® 1002D Nat 1 adopted as the component [E] was added to theepoxy resin composition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for50 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 21, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 3.1×10³ to 1.1×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had good dry property asevaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9) and there was no surface resin remainingon the metal plate after removal by pulling. Furthermore, it hadparticularly good drapability as evaluated by the prepreg drapabilityevaluation procedure described in (10). The prepreg had a glasstransition temperature of 4.2° C. as measured by the prepreg's glasstransition temperature measurement procedure described in (4) and theepoxy resin composition in the prepreg had a degree of conversion of8.6% as measured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of181° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,930 MPa as measured according to (15).

Example 66

An epoxy resin composition 1 was prepared by mixing 50 parts of TOREP®A-204E and 50 parts of Sumiepoxy® ELM434 as the component [B], 45 partsof 3,3′-DAS as the component [C] and 10 parts of Sumikaexcel® PES5003Pas the component [D] according to the epoxy resin compositionpreparation procedure described in (1). Then, 20 parts of Orgasol® 1002DNat 1 adopted as the component [E] was added to the epoxy resincomposition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for50 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 22, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 1.2×10⁴ to 5.5×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had an acceptable level of drapability as evaluatedby the prepreg drapability evaluation procedure described in (10). Theprepreg had a glass transition temperature of 10.5° C. as measured bythe prepreg's glass transition temperature measurement proceduredescribed in (4) and the epoxy resin composition in the prepreg had adegree of conversion of 8.6% as measured by the epoxy resincomposition's degree of conversion measurement procedure described in(8). Furthermore, the mass ratio among the constituents of the component[B] in the prepreg that included a preliminary reaction product ascalculated by the procedure described in (7) showed no change from themass ratio based on the contents of the constituents of the component[B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of191° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,900 MPa as measured according to (15).

Example 67

An epoxy resin composition 1 was prepared by mixing 60 parts of TOREP®A-204E and 40 parts of Sumiepoxy® ELM434 as the component [B], 41 partsof 3,3′-DAS as the component [C] and 10 parts of Sumikaexcel® PES5003Pas the component [D] according to the epoxy resin compositionpreparation procedure described in (1). Then, 20 parts of Orgasol® 1002DNat 1 adopted as the component [E] was added to the epoxy resincomposition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for50 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 22, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 1.0×10⁴ to 5.3×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had good drapability as evaluated by the prepregdrapability evaluation procedure described in (10). The prepreg had aglass transition temperature of 10.1° C. as measured by the prepreg'sglass transition temperature measurement procedure described in (4) andthe epoxy resin composition in the prepreg had a degree of conversion of8.1% as measured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of183° C. as measured according to the procedure described in (13).Furthermore, the carbon fiber reinforced material had a 0° tensilestrength of 2,960 MPa as measured according to (15).

Example 68

An epoxy resin composition 1 was prepared by mixing 70 parts ofSumiepoxy® ELM434 and 30 parts of EPICLON® HP-7200 as the component [B],45 parts of Seikacure-S as the component [C], and 20 parts of Virantage®VW-10700RP as the component [D] according to the epoxy resin compositionpreparation procedure described in (1). Then, 20 parts of Orgasol® 1002DNat 1 adopted as the component [E] was added to the epoxy resincomposition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for75 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 22, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 1.5×10⁴ to 1.1×10⁷ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had an acceptable level of drapability as evaluatedby the prepreg drapability evaluation procedure described in (10). Theprepreg had a glass transition temperature of 12.6° C. as measured bythe prepreg's glass transition temperature measurement proceduredescribed in (4) and the epoxy resin composition in the prepreg had adegree of conversion of 4.3% as measured by the epoxy resincomposition's degree of conversion measurement procedure described in(8). Furthermore, the mass ratio of the component [B] in the prepregthat included a preliminary reaction product as calculated by theprocedure described in (7) showed no change from the mass ratio based onthe contents of the constituents of the component [B] before thepreliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of204° C. as measured according to the procedure described in (13).

Example 69

An epoxy resin composition 1 was prepared by mixing 90 parts ofSumiepoxy® ELM434 and 10 parts of EPICLON® HP-7200 as the component [B],45 parts of Seikacure-S as the component [C], and 20 parts of Virantage®VW-10700RP as the component [D] according to the epoxy resin compositionpreparation procedure described in (1). Then, 20 parts of Orgasol® 1002DNat 1 adopted as the component [E] was added to the epoxy resincomposition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for75 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 22, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 9.4×10³ to 9.1×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had good drapability as evaluated by the prepregdrapability evaluation procedure described in (10). The prepreg had aglass transition temperature of 11.5° C. as measured by the prepreg'sglass transition temperature measurement procedure described in (4) andthe epoxy resin composition in the prepreg had a degree of conversion of4.0% as measured by the epoxy resin composition's degree of conversionmeasurement procedure described in (8). Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of202° C. as measured according to the procedure described in (13).

Example 70

An epoxy resin composition 1 was prepared by mixing 70 parts ofSumiepoxy® ELM434 and 30 parts of jER® YX4000 as the component [B], 45parts of Seikacure-S as the component [C], and 20 parts of Virantage®VW-10700RP as the component [D] according to the epoxy resin compositionpreparation procedure described in (1). Then, 20 parts of Orgasol® 1002DNat 1 adopted as the component [E] was added to the epoxy resincomposition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for75 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 22, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 1.9×10⁴ to 1.5×10⁷ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had an acceptable level of drapability as evaluatedby the prepreg drapability evaluation procedure described in (10). Theprepreg had a glass transition temperature of 13.1° C. as measured bythe prepreg's glass transition temperature measurement proceduredescribed in (4) and the epoxy resin composition in the prepreg had adegree of conversion of 4.8% as measured by the epoxy resincomposition's degree of conversion measurement procedure described in(8). Furthermore, the mass ratio of the component [B] in the prepregthat included a preliminary reaction product as calculated by theprocedure described in (7) showed no change from the mass ratio based onthe contents of the constituents of the component [B] before thepreliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of206° C. as measured according to the procedure described in (13).

Example 71

An epoxy resin composition 1 was prepared by mixing 90 parts ofSumiepoxy® ELM434 and 10 parts of jER® YX4000 as the component [B], 45parts of Seikacure-S as the component [C], and 20 parts of Virantage®VW-10700RP as the component [D] according to the epoxy resin compositionpreparation procedure described in (1). Then, 20 parts of Orgasol® 1002DNat 1 adopted as the component [E] was added to the epoxy resincomposition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for75 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 22, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 1.3×10⁴ to 9.5×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had an acceptable level of drapability as evaluatedby the prepreg drapability evaluation procedure described in (10). Theprepreg had a glass transition temperature of 12.3° C. as measured bythe prepreg's glass transition temperature measurement proceduredescribed in (4) and the epoxy resin composition in the prepreg had adegree of conversion of 4.2% as measured by the epoxy resincomposition's degree of conversion measurement procedure described in(8). Furthermore, the mass ratio among the constituents of the component[B] in the prepreg that included a preliminary reaction product ascalculated by the procedure described in (7) showed no change from themass ratio based on the contents of the constituents of the component[B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of203° C. as measured according to the procedure described in (13).

Example 72

An epoxy resin composition 1 was prepared by mixing 70 parts ofSumiepoxy® ELM434 and 30 parts of EPICLON® HP-4032 as the component [B],55 parts of Seikacure-S as the component [C], and 20 parts of Virantage®VW-10700RP as the component [D] according to the epoxy resin compositionpreparation procedure described in (1). Then, 20 parts of Orgasol® 1002DNat 1 adopted as the component [E] was added to the epoxy resincomposition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for60 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 22, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 1.7×10⁴ to 9.4×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had an acceptable level of drapability as evaluatedby the prepreg drapability evaluation procedure described in (10). Theprepreg had a glass transition temperature of 12.4° C. as measured bythe prepreg's glass transition temperature measurement proceduredescribed in (4) and the epoxy resin composition in the prepreg had adegree of conversion of 5.3% as measured by the epoxy resincomposition's degree of conversion measurement procedure described in(8). Furthermore, the mass ratio of the component [B] in the prepregthat included a preliminary reaction product as calculated by theprocedure described in (7) showed no change from the mass ratio based onthe contents of the constituents of the component [B] before thepreliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of203° C. as measured according to the procedure described in (13).

Example 73

An epoxy resin composition 1 was prepared by mixing 90 parts ofSumiepoxy® ELM434 and 10 parts of EPICLON® HP-4032 as the component [B],55 parts of Seikacure-S as the component [C], and 20 parts of Virantage®VW-10700RP as the component [D] according to the epoxy resin compositionpreparation procedure described in (1). Then, 20 parts of Orgasol® 1002DNat 1 adopted as the component [E] was added to the epoxy resincomposition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was heat-treated for60 hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [B] and[C] to be contained in the prepreg.

As shown in Table 22, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 9.0×10³ to 8.3×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had particularly good dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and there was no surfaceresin remaining on the metal plate after removal by pulling.Furthermore, it also had an acceptable level of drapability as evaluatedby the prepreg drapability evaluation procedure described in (10). Theprepreg had a glass transition temperature of 11.0° C. as measured bythe prepreg's glass transition temperature measurement proceduredescribed in (4) and the epoxy resin composition in the prepreg had adegree of conversion of 5.1% as measured by the epoxy resincomposition's degree of conversion measurement procedure described in(8). Furthermore, the mass ratio among the constituents of the component[B] in the prepreg that included a preliminary reaction product ascalculated by the procedure described in (7) showed no change from themass ratio based on the contents of the constituents of the component[B] before the preliminary reaction.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of201° C. as measured according to the procedure described in (13).

Comparative Examples 1 and 2

Except for changing the heat treatment time of the prepreg precursor asspecified in Table 10, the same procedure as in Example 1 was carriedout to prepare a prepreg.

As shown in Table 23, the prepreg prepared in Comparative example 1,which contained a surface resin having a minimum G′ value of less than1.0×10³ as measured at a temperature of 40° C. and an angular frequencyin the range of 0.06 to 314 rad/s, had particularly high drapability,but the tackiness between the prepreg and metal was so large that partof the surface resin remained on the metal plate after removal bypulling, indicating that the prepreg was not sufficiently good in dryproperty. Furthermore, the prepreg prepared in Comparative example 2,which contained a surface resin having a maximum G′ value of more than2.0×10⁸ as measured at a temperature of 40° C. and an angular frequencyin the range of 0.06 to 314 rad/s, had good dry property, but theprepreg was so hard that its drapability was low and outside thepermissible range. Other measurement results are shown in Table 23.Furthermore, the mass ratio among the constituents of the component [B]in the prepreg that included a preliminary reaction product ascalculated by the procedure described in (7) showed no change from themass ratio based on the contents of the constituents of the component[B] before the preliminary reaction.

Comparative Examples 3 and 4

Except for changing the heat treatment time of the prepreg precursor asspecified in Table 10, the same procedure as in Example 9 was carriedout to prepare a prepreg.

As shown in Table 23, the prepreg prepared in Comparative example 3,which contained a surface resin having a minimum G′ value of less than1.0×10³ as measured at a temperature of 40° C. and an angular frequencyin the range of 0.06 to 314 rad/s, had particularly high drapability,but the tackiness between the prepreg and metal was so large that partof the surface resin remained on the metal plate after removal bypulling, indicating that the prepreg was not sufficiently good in dryproperty. Furthermore, the prepreg prepared in Comparative example 4,which contained a surface resin having a maximum G′ value of more than2.0×10⁸ as measured at a temperature of 40° C. and an angular frequencyin the range of 0.06 to 314 rad/s, had good dry property, but theprepreg was so hard that its drapability was low and outside thepermissible range. Other measurement results are shown in Table 23.Furthermore, the mass ratio among the constituents of the component [B]in the prepreg that included a preliminary reaction product ascalculated by the procedure described in (7) showed no change from themass ratio based on the contents of the constituents of the component[B] before the preliminary reaction.

Comparative Examples 5 and 6

Except for changing the heat treatment time of the prepreg precursor asspecified in Table 10, the same procedure as in Example 12 was carriedout to prepare a prepreg.

As shown in Table 23, the prepreg prepared in Comparative example 5,which contained a surface resin having a minimum G′ value of less than1.0×10³ as measured at a temperature of 40° C. and an angular frequencyin the range of 0.06 to 314 rad/s, had particularly high drapability,but the tackiness between the prepreg and metal was so large that partof the surface resin remained on the metal plate after removal bypulling, indicating that the prepreg was not sufficiently good in dryproperty. Furthermore, the prepreg prepared in Comparative example 6,which contained a surface resin having a maximum G′ value more than2.0×10⁸ as measured at a temperature of 40° C. and an angular frequencyin the range of 0.06 to 314 rad/s, had good dry property, but theprepreg was so hard that its drapability was low and outside thepermissible range. Other measurement results are shown in Table 23.Furthermore, the mass ratio among the constituents of the component [B]in the prepreg that included a preliminary reaction product ascalculated by the procedure described in (7) showed no change from themass ratio based on the contents of the constituents of the component[B] before the preliminary reaction.

Comparative Example 7

An epoxy resin composition 1 was prepared by mixing 50 parts of jER® 630and 50 parts of jER® 1055 as the component [B], 35 parts of Seikacure-Sas the component [C], and 35 parts of Virantage® VW-10700RP as thecomponent [D] according to the epoxy resin composition preparationprocedure described in (1). Then, 25 parts of Orgasol® 1002D Nat 1adopted as the component [E] was added to the epoxy resin composition 1to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T8005-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was not heat-treatedand the prepreg was free of a preliminary reaction product of [B] and[C].

As shown in Table 23, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 1.0×10³ to 2.0×10⁸ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had an acceptable level of dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9). It had good drapability asevaluated by the prepreg drapability evaluation procedure described in(10). However, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of170° C., which is outside the permissible range, as measured accordingto the procedure described in (13) above. Other measurement results areshown in Table 23. Furthermore, the mass ratio among the constituents ofthe component [B] in the prepreg that included a preliminary reactionproduct as calculated by the procedure described in (7) showed no changefrom the mass ratio based on the contents of the constituents of thecomponent [B] before the preliminary reaction.

Comparative Example 8

Except for using 80 parts, instead of 50 parts, of jER® 630 and 20parts, instead of 50 parts, of jER® 1055 as the component [B], the sameprocedure as Comparative Example 7 was carried out to prepare a prepreg.

As shown in Table 23, the carbon fiber reinforced material cured by theprepreg curing procedure described in (12) above had a glass transitiontemperature of 180° C., which is outside the permissible range, asmeasured according to the procedure described in (13) above, but theprepreg prepared, which contained a surface resin having a minimum G′value of less than 1.0×10³ as measured at a temperature of 40° C. and anangular frequency in the range of 0.06 to 314 rad/s, had particularlyhigh drapability, but the tackiness between the prepreg and metal was solarge that part of the surface resin remained on the metal plate afterremoval by pulling, indicating that the prepreg was not sufficientlygood in dry property. Other measurement results are shown in Table 23.Furthermore, the mass ratio among the constituents of the component [B]in the prepreg that included a preliminary reaction product ascalculated by the procedure described in (7) showed no change from themass ratio based on the contents of the constituents of the component[B] before the preliminary reaction.

Comparative Examples 9 and 10

Except for changing the heat treatment time of the prepreg precursor asspecified in Table 11, the same procedure as in Example 18 was carriedout to prepare a prepreg.

As shown in Table 24, the prepreg prepared in Comparative example 9,which contained a surface resin having a minimum G′ value of less than1.0×10³ as measured at a temperature of 40° C. and an angular frequencyin the range of 0.06 to 314 rad/s, had particularly high drapability,but the tackiness between the prepreg and metal was so large that partof the surface resin remained on the metal plate after removal bypulling, indicating that the prepreg was not sufficiently good in dryproperty. Furthermore, the prepreg prepared in Comparative example 10,which contained a surface resin having a maximum G′ value of more than2.0×10⁸ as measured at a temperature of 40° C. and an angular frequencyin the range of 0.06 to 314 rad/s, had good dry property, but theprepreg was so hard that its drapability was low and outside thepermissible range. Furthermore, the mass ratio among the constituents ofthe component [B] in the prepreg that included a preliminary reactionproduct as calculated by the procedure described in (7) showed no changefrom the mass ratio based on the contents of the constituents of thecomponent [B] before the preliminary reaction. Other measurement resultsare shown in Table 24. Furthermore, electron microscopic observationshowed that the cured prepreg produced by curing the prepreg ofComparative examples 1 and 2 had a sea-island type phase-separatedstructure.

Comparative Example 11

Except for using 50 parts of jER® 1055 instead of 50 parts of jER® 807as the component [B], the same procedure as Comparative Example 1 wascarried out to prepare a prepreg precursor. The resulting prepregprecursor was not heat-treated and the prepreg was free of a preliminaryreaction product of [B] and [C].

As shown in Table 24, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 1.0×10³ to 2.0×10⁸ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had an acceptable level of dryproperty and high drapability as evaluated based on measurements of thetackiness between prepreg and metal taken as described in (9) and basedon the prepreg drapability evaluation procedure described in (10).However, the cured prepreg cured by the prepreg curing proceduredescribed in (12) had a glass transition temperature of 170° C., whichwas lower by 35° C. than in Comparative example 1, as measured accordingto the procedure described in (13) above. Furthermore, the mass ratioamong the constituents of the component [B] in the prepreg that includeda preliminary reaction product as calculated by the procedure describedin (7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction. Othermeasurement results are shown in Table 4. Furthermore, electronmicroscopic observation showed that the cured prepreg had a sea-islandtype phase-separated structure.

Comparative Example 12

Except for using 70 parts, instead of 50 parts, of jER® 630 and 30parts, instead of 50 parts, of jER® 1055 as the component [B], the sameprocedure as Comparative Example 11 was carried out to prepare a prepregprecursor. The resulting prepreg precursor was not heat-treated and theprepreg was free of a preliminary reaction product of [B] and [C].

As shown in Table 24, the cured prepreg cured by the prepreg curingprocedure described in (12) above had a glass transition temperature of185° C., which is in the permissible range, as measured according to theprocedure described in (13) above, but the prepreg prepared, whichcontained a surface resin having a minimum G′ value of less than 1.0×10³as measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s, had particularly high drapability, but thetackiness between the prepreg and metal was so large that part of thesurface resin remained on the metal plate after removal by pulling,indicating that the prepreg was not sufficiently good in dry property.Furthermore, the mass ratio among the constituents of the component [B]in the prepreg that included a preliminary reaction product ascalculated by the procedure described in (7) showed no change from themass ratio based on the contents of the constituents of the component[B] before the preliminary reaction. Other measurement results are shownin Table 24. Furthermore, electron microscopic observation showed thatthe cured prepreg had a sea-island type phase-separated structure.

Comparative Examples 13 and 14

Except for changing the heat treatment time of the prepreg precursor asspecified in Table 11, the same procedure as in Example 29 was carriedout to prepare a prepreg.

As shown in Table 24, the prepreg prepared in Comparative example 13,which contained a surface resin having a minimum G′ value of less than1.0×10³ as measured at a temperature of 40° C. and an angular frequencyin the range of 0.06 to 314 rad/s, had particularly high drapability asevaluated according to the prepreg drapability evaluation proceduredescribed in (10), but the tackiness between the prepreg and metal wasso large that part of the surface resin remained on the metal plateafter removal by pulling, resulting in a poor prepreg dry property asevaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9). Furthermore, the prepreg prepared inComparative example 14, which contained a surface resin having a maximumG′ value of more than 2.0×10⁸ as measured at a temperature of 40° C. andan angular frequency in the range of 0.06 to 314 rad/s, had particularlygood dry property, but the prepreg was so hard that its drapability waslow and outside the permissible range. Other measurement results areshown in Table 13. Furthermore, the mass ratio among the constituents ofthe component [B] in the prepreg that included a preliminary reactionproduct as calculated by the procedure described in (7) showed no changefrom the mass ratio based on the contents of the constituents of thecomponent [B] before the preliminary reaction.

Comparative Examples 15 and 16

Except for changing the heat treatment time of the prepreg precursor asspecified in Table 11, the same procedure as in Example 42 was carriedout to prepare a prepreg.

As shown in Table 24, the prepreg prepared in Comparative example 15,which contained a surface resin having a minimum G′ value of less than1.0×10³ as measured at a temperature of 40° C. and an angular frequencyin the range of 0.06 to 314 rad/s, had particularly high drapability asevaluated according to the prepreg drapability evaluation proceduredescribed in (10), but the tackiness between the prepreg and metal wasso large that part of the surface resin remained on the metal plateafter removal by pulling, resulting in a poor prepreg dry property asevaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9). Furthermore, the prepreg prepared inComparative example 16, which contained a surface resin having a maximumG′ value of more than 2.0×10⁸ as measured at a temperature of 40° C. andan angular frequency in the range of 0.06 to 314 rad/s, had particularlygood dry property, but the prepreg was so hard that its drapability waslow and outside the permissible range. Other measurement results areshown in Table 13. Furthermore, the mass ratio among the constituents ofthe component [B] in the prepreg that included a preliminary reactionproduct as calculated by the procedure described in (7) showed no changefrom the mass ratio based on the contents of the constituents of thecomponent [B] before the preliminary reaction.

Comparative Examples 17 and 18

Except for changing the heat treatment time of the prepreg precursor asspecified in Tables 11 and 12, the same procedure as in Example 55 wascarried out to prepare a prepreg.

As shown in Tables 24 and 25, the prepreg prepared in Comparativeexample 17, which contained a surface resin having a minimum G′ value ofless than 1.0×10³ as measured at a temperature of 40° C. and an angularfrequency in the range of 0.06 to 314 rad/s, had particularly highdrapability as evaluated according to the prepreg drapability evaluationprocedure described in (10), but the tackiness between the prepreg andmetal was so large that part of the surface resin remained on the metalplate after removal by pulling, resulting in a poor prepreg dry propertyas evaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9). Furthermore, the prepreg prepared inComparative example 18, which contained a surface resin having a maximumG′ value of more than 2.0×10⁸ as measured at a temperature of 40° C. andan angular frequency in the range of 0.06 to 314 rad/s, had particularlygood dry property, but the prepreg was so hard that its drapability waslow and outside the permissible range. Other measurement results areshown in Table 13. Furthermore, the mass ratio among the constituents ofthe component [B] in the prepreg that included a preliminary reactionproduct as calculated by the procedure described in (7) showed no changefrom the mass ratio based on the contents of the constituents of thecomponent [B] before the preliminary reaction.

Comparative Example 19

An epoxy resin composition 1 was prepared by mixing 20 parts of Denacol®EX-731, 60 parts of Sumiepoxy® ELM434, and 20 parts of jER® 1055 as thecomponent [B], 40 parts of Seikacure-S as the component [C], and 10parts of Sumikaexcel® PES5003P as the component [D] according to theepoxy resin composition preparation procedure described in (1). Then, 20parts of Orgasol® 1002D Nat 1 adopted as the component [E] was added tothe epoxy resin composition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was not heat-treatedand the prepreg was free of a preliminary reaction product of [B] and[C].

As shown in Table 25, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 4.3×10³ to 8.0×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had an acceptable level of dryproperty and drapability as evaluated based on measurements of thetackiness between prepreg and metal taken as described in (9) and basedon the prepreg drapability evaluation procedure described in (10).However, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of163° C., which is outside the permissible range, as measured accordingto the procedure described in (13) above. Other measurement results areshown in Table 25.

Comparative Example 20

An epoxy resin composition 1 was prepared by mixing 20 parts of GAN, 60parts of Sumiepoxy® ELM434, and 20 parts of jER® 1055 as the component[B], 45 parts of Seikacure-S as the component [C], and 10 parts ofSumikaexcel® PES5003P as the component [D] according to the epoxy resincomposition preparation procedure described in (1). Then, 20 parts ofOrgasol® 1002D Nat 1 adopted as the component [E] was added to the epoxyresin composition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was not heat-treatedand the prepreg was free of a preliminary reaction product of [B] and[C].

As shown in Table 25, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 1.3×10³ to 4.9×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had an acceptable level of dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9). It had good drapability asevaluated by the prepreg drapability evaluation procedure described in(10). However, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of169° C., which is outside the permissible range, as measured accordingto the procedure described in (13) above. Other measurement results areshown in Table 25.

Comparative Example 21

An epoxy resin composition 1 was prepared by mixing 20 parts of TOREP(registered trademark) A-204E, 60 parts of Sumiepoxy® ELM434, and 20parts of jER® 1055 as the component [B], 45 parts of 3,3′-DAS as thecomponent [C], and 10 parts of Sumikaexcel® PES5003P as the component[D] according to the epoxy resin composition preparation proceduredescribed in (1). Then, 20 parts of Orgasol® 1002D Nat 1 adopted as thecomponent [E] was added to the epoxy resin composition 1 to prepare anepoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was not heat-treatedand the prepreg was free of a preliminary reaction product of [B] and[C].

As shown in Table 25, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 1.6×10³ to 5.3×10⁶ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had an acceptable level of dryproperty as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9). It had good drapability asevaluated by the prepreg drapability evaluation procedure described in(10). However, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of171° C., which is outside the permissible range, as measured accordingto the procedure described in (13) above. Other measurement results areshown in Table 25.

Comparative Examples 22 and 23

Except for changing the heat treatment time of the prepreg precursor asspecified in Table 12, the same procedure as in Example 68 was carriedout to prepare a prepreg.

As shown in Table 25, the prepreg prepared in Comparative example 22,which contained a surface resin having a minimum G′ value of less than1.0×10³ as measured at a temperature of 40° C. and an angular frequencyin the range of 0.06 to 314 rad/s, had particularly high drapability asevaluated according to the prepreg drapability evaluation proceduredescribed in (10), but the tackiness between the prepreg and metal wasso large that some of the surface resin remained on the metal plateafter removal by pulling, resulting in a poor prepreg dry property asevaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9). Furthermore, the prepreg prepared inComparative example 23, which contained a surface resin having a maximumG′ value of more than 2.0×10⁸ Pa as measured at a temperature of 40° C.and an angular frequency in the range of 0.06 to 314 rad/s, hadparticularly good dry property, but the prepreg was so hard that itsdrapability was low and outside the permissible range. Other measurementresults are shown in Table 25. Furthermore, the mass ratio among theconstituents of the component [B] in the prepreg that included apreliminary reaction product as calculated by the procedure described in(7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

Comparative Examples 24 and 25

Except for changing the heat treatment time of the prepreg precursor asspecified in Table 12, the same procedure as in Example 70 was carriedout to prepare a prepreg.

As shown in Table 25, the prepreg prepared in Comparative example 24,which contained a surface resin having a minimum G′ value of less than1.0×10³ as measured at a temperature of 40° C. and an angular frequencyin the range of 0.06 to 314 rad/s, had particularly high drapability asevaluated according to the prepreg drapability evaluation proceduredescribed in (10), but the tackiness between the prepreg and metal wasso large that some of the surface resin remained on the metal plateafter removal by pulling, resulting in a poor prepreg dry property asevaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9). Furthermore, the prepreg prepared inComparative example 25, which contained a surface resin having a maximumG′ value of more than 2.0×10⁸ as measured at a temperature of 40° C. andan angular frequency in the range of 0.06 to 314 rad/s, had particularlygood dry property, but the prepreg was so hard that its drapability waslow and outside the permissible range. Other measurement results areshown in Table 25. Furthermore, the mass ratio among the constituents ofthe component [B] in the prepreg that included a preliminary reactionproduct as calculated by the procedure described in (7) showed no changefrom the mass ratio based on the contents of the constituents of thecomponent [B] before the preliminary reaction.

Comparative Examples 26 and 27

Except for changing the heat treatment time of the prepreg precursor asspecified in Tables 12 and 13, the same procedure as in Example 72 wascarried out to prepare a prepreg.

As shown in Tables 25 and 26, the prepreg prepared in Comparativeexample 26, which contained a surface resin having a minimum G′ value ofless than 1.0×10³ as measured at a temperature of 40° C. and an angularfrequency in the range of 0.06 to 314 rad/s, had particularly highdrapability as evaluated according to the prepreg drapability evaluationprocedure described in (10), but the tackiness between the prepreg andmetal was so large that part of the surface resin remained on the metalplate after removal by pulling, resulting in a poor prepreg dry propertyas evaluated based on measurements of the tackiness between prepreg andmetal taken as described in (9). Furthermore, the prepreg prepared inComparative example 27, which contained a surface resin having a maximumG′ value of more than 2.0×10⁸ as measured at a temperature of 40° C. andan angular frequency in the range of 0.06 to 314 rad/s, had particularlygood dry property, but the prepreg was so hard that its drapability waslow and outside the permissible range. Other measurement results areshown in Tables 25 and 26. Furthermore, the mass ratio among theconstituents of the component [B] in the prepreg that included apreliminary reaction product as calculated by the procedure described in(7) showed no change from the mass ratio based on the contents of theconstituents of the component [B] before the preliminary reaction.

Comparative Example 28

An epoxy resin composition 1 was prepared by mixing 80 parts ofSumiepoxy® ELM434 and 20 parts of jER® 1055 as the component [B], 30parts of Seikacure-S as the component [C], and 14 parts of Sumikaexcel®PES5003P as the component [D] according to the epoxy resin compositionpreparation procedure described in (1). Then, 20 parts of Orgasol® 1002DNat 1 adopted as the component [E] was added to the epoxy resincomposition 1 to prepare an epoxy resin composition 2.

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin compositions 1 and 2 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3). The resulting prepreg precursor was not heat-treatedand the prepreg was free of a preliminary reaction product of [C] and[D].

As shown in Table 26, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 3.1×10⁴ to 2.0×10⁷ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s, and the prepreg had good drapability asevaluated by the prepreg drapability evaluation procedure described in(10). Compared to this, the tackiness between the prepreg and metal wasslightly large and a small amount of the surface resin remained on themetal plate after removal by pulling. Other measurement results areshown in Table 26.

Comparative Examples 29 and 30

Except for using Sumikaexcel® PES5003P as the component [B] in amountsas specified in Table 7, the same procedure as Comparative example 28was carried out to prepare a prepreg.

The prepreg of Comparative example 29 had high drapability as evaluatedaccording to the prepreg drapability evaluation procedure described in(10), but the tackiness between the prepreg and metal was slightly largeand a small amount of the surface resin remained on the metal plateafter removal by pulling.

The prepreg of Comparative example 30 was lower in dry property anddrapability as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and based on the prepregdrapability evaluation procedure described in (10) as compared to theprepregs obtained in Examples 29 to 67.

Comparative Example 31

Except for using 60 parts, instead of 80 parts, of Sumiepoxy® ELM434 and40 parts, instead of 20 parts, of jER® 1055 as the component [B], thesame procedure as Comparative example 28 was carried out to prepare aprepreg.

As shown in Table 26, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 1.5×10⁵ to 1.1×10⁸ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had good dry property and highdrapability as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and based on the prepregdrapability evaluation procedure described in (10) above. However, thecarbon fiber reinforced material cured by the prepreg curing proceduredescribed in (12) had a glass transition temperature of 180° C., whichwas lower by 15° C. than in Comparative example 28, as measuredaccording to the procedure described in (13) above. Other measurementresults are shown in Table 26.

Comparative Example 32

Except for using 20 parts of jER® 819 instead of 20 parts of jER® 1055as the component [B], the same procedure as Comparative Example 28 wascarried out to prepare a prepreg.

As shown in Table 14, the prepreg prepared, which contained a surfaceresin having a G′ value in the range of 1.5×10³ to 9.2×10⁵ Pa asmeasured at a temperature of prepreg prepared a 40° C. and an angularfrequency in the range of 0.06 to 314 rad/s, had particularly highdrapability, but the tackiness between the prepreg and metal was solarge that part of the surface resin remained on the metal plate afterremoval by pulling, indicating that the prepreg was not sufficientlygood in dry property. Other measurement results are shown in Table 26.

Comparative Example 33

An epoxy resin composition 1 was prepared by mixing 50 parts ofSumiepoxy® ELM434 and 50 parts of jER® 825 as the component [B] and 30parts of Seikacure-S as the component [C] according to the epoxy resincomposition preparation procedure described in (1).

Furthermore, using Torayca® T800S-24K-10E as the component [A] and theepoxy resin composition 1 prepared above, a prepreg precursor wasproduced according to the prepreg precursor preparation proceduredescribed in (3) above. The resulting prepreg was heat-treated for 190hours according to the prepreg precursor heat-treatment proceduredescribed in (5) to allow the preliminary reaction product of [C] and[D] to be contained in the prepreg.

As shown in Table 26, the surface resin in the prepreg prepared abovehad a storage elastic modulus G′ in the range of 1.2×10³ to 8.5×10⁵ Paas measured at a temperature of 40° C. and an angular frequency in therange of 0.06 to 314 rad/s. The prepreg had inferior dry property anddrapability as evaluated based on measurements of the tackiness betweenprepreg and metal taken as described in (9) and based on the prepregdrapability evaluation procedure described in (10) as compared to theprepregs obtained in Examples 19 to 67. In addition, this prepreg had aglass transition temperature of 5.8° C. and the epoxy resin compositionin the prepreg had a degree of conversion of 25.2%.

In addition, the carbon fiber reinforced material cured by the prepregcuring procedure described in (12) had a glass transition temperature of190° C. as measured according to the procedure described in (13).

Comparative Example 34

Except for changing the heat treatment time of the prepreg as specifiedin Table 13, the same procedure as Comparative example 33 was carriedout to prepare a prepreg.

As shown in Table 26, the surface resin in the prepreg prepared abovehad a G′ value in the range of 2.6×10³ to 1.6×10⁶ Pa as measured at atemperature of 40° C. and an angular frequency in the range of 0.06 to314 rad/s. The prepreg had good dry property as evaluated based onmeasurements of the tackiness between prepreg and metal taken asdescribed in (9). Compared to this, the drapability was slightly loweras compared to Examples 33. Other measurement results are shown in Table26.

It can be seen from the comparisons between Examples 1 to 8 andComparative examples 1 and 2, between Examples 9 to 11 and Comparativeexamples 3 and 4, and between Examples 12 to 14 and Comparative examples5 and 6 that a prepreg including the components [A] to [E] andcontaining a preliminary reaction product of [B] and [C] has a highdrapability but suffers from an excessive tackiness between the prepregand metal when the surface resin contained has a minimum G′ value ofless than 1.0×10³ Pa as measured at a temperature of 40° C. and anangular frequency in the range of 0.06 to 314 rad/s. It is also seenthat a sufficient drapability cannot be realized when the maximum valueof G′ is more than 2.0×10⁸ Pa although a good tackiness is realizedbetween the prepreg and metal.

It can be seen from the comparison between Examples 1 to 8 andComparative examples 7 and 8 that when the G′ value is controlled byincreasing the molecular weight of the bisphenol A epoxy, instead ofcontrolling the G′ value by including a preliminary reaction product,the carbon fiber reinforced material necessarily suffers a decrease inglass transition temperature if an attempt is made to obtain a prepregthat has both good dry property and high drapability.

It can be seen from the comparison between Examples 1 to 17 andComparative examples 28 to 32 that when the G′ value is controlled byeliminating the aminophenol epoxy resin, increasing the molecular weightof the bisphenol A epoxy, changing the content of the thermoplasticresin, or adopting a combination thereof, instead of controlling the G′value by including a preliminary reaction product, realizing both gooddry property and high drapability at levels similar to those in Examples1 to 17 is difficult without undergoing a decrease in glass transitiontemperature of the carbon fiber reinforced material.

It can be seen from the comparison between Examples 1 to 17 andComparative examples 33 and 34 that if the prepreg does not contain athermoplastic resin, the inclusion of a preliminary reaction productalone, which is realized by heat treatment, cannot serve to realize gooddry property unless the epoxy resin composition in the prepreg has adegree of conversion of 20% or more and it is difficult to realize ahigh drapability at a level similar to that in Examples 1 to 17.

It can be seen from the comparisons between Examples 18 to 28 andComparative examples 9 and 10 that a prepreg including the components[A] to [D] and containing a preliminary reaction product of components[B] and [C] has a high drapability but suffers from an excessivetackiness between the prepreg and metal when the surface resin containedhas a minimum G′ value of less than 1.0×10³ Pa as measured at atemperature of 40° C. and an angular frequency in the range of 0.06 to314 rad/s. It is also seen that a sufficient drapability cannot berealized when the maximum value of G′ is more than 2.0×10⁸ Pa although agood tackiness is realized between the prepreg and metal.

It can be seen from the comparison between Examples 18 to 28 andComparative examples 11 and 12 that when the G′ value is controlled byincreasing the molecular weight of the bisphenol A epoxy resin, insteadof controlling the G′ value by including a preliminary reaction product,the cured prepreg necessarily suffers a decrease in glass transitiontemperature if an attempt is made to obtain a prepreg that has both gooddry property and high drapability.

It can be seen from the comparison between Examples 18 to 28 andComparative examples 28 to 32 that when the G′ value is controlled byeliminating the aminophenol epoxy resin, increasing the molecular weightof the bisphenol A epoxy resin, changing the content of thethermoplastic resin, or adopting a combination thereof, instead ofcontrolling the G′ value by including a preliminary reaction product,realizing both good dry property and high drapability at levels similarto those in Examples 18 to 28 is difficult without undergoing a decreasein glass transition temperature of the cured prepreg.

It can be seen from the comparison between Examples 18 to 28 andComparative examples 33 and 34 that if the prepreg does not contain athermoplastic resin, the inclusion of a preliminary reaction productalone, which is realized by heat treatment, cannot serve to realize gooddry property unless the epoxy resin composition in the prepreg has adegree of conversion of 20% or more and it is difficult to realize ahigh drapability at a level similar to that in Examples 18 to 28.

It can be seen from the comparisons between Examples 29 to 41 andComparative examples 31 and 32, between Examples 42 to 54 andComparative examples 33 and 34, and between Examples 55 to 67 andComparative examples 17 and 18 that a prepreg including the components[A] to [E] and containing a preliminary reaction product of [B] and [C]has a high drapability but suffers from an excessive tackiness betweenthe prepreg and metal when the surface resin contained has a minimum G′value of less than 1.0×10³ Pa as measured at a temperature of 40° C. andan angular frequency in the range of 0.06 to 314 rad/s. It is also seenthat a sufficient drapability cannot be realized when the maximum valueof G′ is more than 2.0×10⁸ Pa although a good tackiness is realizedbetween the prepreg and metal.

It can be seen from the comparison between Examples 29 to 41 andComparative example 19, between Examples 42 to 54 and Comparativeexample 20, and between Examples 55 to 67 and Comparative example 20that when the G′ value is controlled by adding a high molecular weighttype bisphenol A epoxy, instead of controlling the G′ value by includinga preliminary reaction product, the carbon fiber reinforced materialnecessarily suffers a large decrease in glass transition temperature ifan attempt is made to obtain a prepreg that has both good dry propertyand high drapability.

It can be seen from the comparison between Examples 29 to 67 andComparative examples 28 to 32 that when the G′ value is controlled byeliminating the component [B], adding a high molecular weight typebisphenol A epoxy, changing the content of the thermoplastic resin, oradopting a combination thereof, instead of controlling the G′ value byincluding a preliminary reaction product, it is difficult to realizeboth good dry property and high drapability at levels similar to thosein Examples 29 to 67 while maintaining both high heat resistance andhigh low-temperature mechanical strength.

It can be seen from the comparison between Examples 29 to 67 andComparative examples 33 and 34 that if the prepreg does not contain athermoplastic resin, the inclusion of a preliminary reaction productalone cannot serve to realize both good dry property unless the epoxyresin composition in the prepreg has a degree of conversion of 20% ormore and it is difficult to realize good dry property and highdrapability at levels similar to those in Examples 29 to 67.

The present investigation provides a prepreg and a carbon fiberreinforced material having high fire retardance and heat resistance aswell as good mechanical property which can serve for aerospaceapplications including, for instance, primary structural members ofaircraft such as main wing, and fuselage; secondary structural memberssuch as tail unit, floor beam, flap, aileron, cowl, fairing, and otherinterior materials; and others such as rocket motor case and structuralmembers of artificial satellites. Their preferred applications forgeneral industrial uses include structural members of vehicles such asautomobiles, ships, and railroad vehicles; and civil engineering andconstruction materials such as drive shafts, plate springs, windmillblades, various turbines, pressure vessels, flywheels, rollers for papermanufacture, roofing materials, cables, reinforcing bars, andmending/reinforcing materials. Preferred applications in the sportinggoods industry include golf shafts, fishing poles, rackets for tennis,badminton, squash, etc., hockey sticks, and skiing poles.

1. A prepreg comprising at least the components [A] to [D] given belowand a preliminary reaction product that is a reaction product of thecomponent [B] and the component [C], the component [B] comprising a m-or p-aminophenol epoxy resin [b1] and either a glycidyl ether epoxyresin or a glycidyl amine epoxy resin [b2] that has two or more glycidylgroups in a molecule, and the component [b1] in the prepreg includingthe preliminary reaction product accounts for 10 to 60 parts by masswhereas the component [b2] in the prepreg including the preliminaryreaction product accounts for 40 to 90 parts by mass relative to thetotal quantity, which accounts for 100 parts by mass, of the component[B] in the prepreg including the preliminary reaction product, the epoxyresin composition, that is, the remainder of the prepreg deprived of thecomponent [A], having a degree of conversion, which is defined in theDescription, of 1% or more and 20% or less, at least one surface resinin the prepreg having a storage elastic modulus G′ in the range of1.0×10³ to 2.0×10⁸ Pa as measured at a temperature of 40° C. and anangular frequency in the range of 0.06 to 314 rad/s: [A] carbon fiber,[B] epoxy resin, [C] curing agent, and [D] thermoplastic resin.
 2. Aprepreg as set forth in claim 1, wherein one surface and the othersurface of the prepreg differ in the storage elastic modulus G′ of theprepreg surface resin measured at a temperature of 40° C. and an angularfrequency in the range of 0.06 to 314 rad/s.
 3. A prepreg as set forthin claim 2, wherein the prepreg surface having the surface resin that isthe smaller in storage elastic modulus G′ is in contact with a coverfilm.
 4. A prepreg as set forth in claim 1, wherein the epoxy resincomposition, that is, the remainder of the prepreg deprived of thecomponent [A], has a glass transition temperature in the range of −5° C.to 20° C. as measured by differential scanning calorimetry (DSC).
 5. Aslit tape prepreg produced by slitting a prepreg as set forth inclaim
 1. 6. A method of producing the prepreg as set forth in claim 1comprising a step of performing heat treatment or energy irradiation ofa prepreg precursor comprising at least the components [A] to [D] toprovide the prepreg.
 7. A method of producing the prepreg as set forthin claim 1 comprising a step of performing heat treatment or energyirradiation of an epoxy resin composition comprising at least thecomponents [B] to [D] and a subsequent step of impregnating thecomponent [A] therewith to provide the prepreg.
 8. A method of producingthe prepreg as set forth in claim 7, wherein the prepreg has aphase-separated structure in which there is phase separation between aphase containing the reaction product of the component [B] and thecomponent [C] as main component and a phase containing the component [D]as main component.
 9. A prepreg as set forth in claim 1, wherein theepoxy resin composition, that is, the remainder of the prepreg deprivedof the component [A], has a degree of conversion, which is defined inthe Description, of 2% or more.
 10. A prepreg as set forth in claim 1,wherein the component [D] is thermoplastic resins having a polyarylether skeleton.
 11. A prepreg as set forth in claim 1, wherein thecomponent [b1] is at least one selected from the group consisting ofepoxy resins having structures as represented by the formula (2) givenbelow, and derivatives thereof: [Chemical formula 2]

wherein R³ and R⁴ in formula (2) represent at least one selected fromthe group consisting of a hydrogen atom, aliphatic hydrocarbon groupcontaining 1 to 4 carbon atoms, alicyclic hydrocarbon group containing 4or less carbon atoms, and halogen atom.